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After an AJAX request, sometimes my application may return an empty object, like:
var a = {};
How can I check whether that's the case?
ECMA 5+:
// because Object.keys(new Date()).length === 0;
// we have to do some additional check
obj // 👈 null and undefined check
&& Object.keys(obj).length === 0
&& Object.getPrototypeOf(obj) === Object.prototype
Note, though, that this creates an unnecessary array (the return value of keys).
Pre-ECMA 5:
function isEmpty(obj) {
for(var prop in obj) {
if(Object.prototype.hasOwnProperty.call(obj, prop)) {
return false;
}
}
return JSON.stringify(obj) === JSON.stringify({});
}
jQuery:
jQuery.isEmptyObject({}); // true
lodash:
_.isEmpty({}); // true
Underscore:
_.isEmpty({}); // true
Hoek
Hoek.deepEqual({}, {}); // true
ExtJS
Ext.Object.isEmpty({}); // true
AngularJS (version 1)
angular.equals({}, {}); // true
Ramda
R.isEmpty({}); // true
If ECMAScript 5 support is available, you can use Object.keys():
function isEmpty(obj) {
return Object.keys(obj).length === 0;
}
For ES3 and older, there's no easy way to do this. You'll have to loop over the properties explicitly:
function isEmpty(obj) {
for(var prop in obj) {
if(obj.hasOwnProperty(prop))
return false;
}
return true;
}
For those of you who have the same problem but use jQuery, you can use jQuery.isEmptyObject.
Performance
Today 2020.01.17, I performed tests on macOS High Sierra 10.13.6 on Chrome v79.0, Safari v13.0.4, and Firefox v72.0; for the chosen solutions.
Conclusions
Solutions based on for-in (A, J, L, M) are fastest
Solutions based on JSON.stringify (B, K) are slow
Surprisingly, the solution based on Object (N) is also slow
NOTE: This table does not match the photo below.
Details
There are 15 solutions presented in the snippet below.
If you want to run a performance test on your machine, click HERE.
This link was updated 2021.07.08, but tests originally were performed here - and results in the table above came from there (but now it looks like that service no longer works).
var log = (s, f) => console.log(`${s} --> {}:${f({})} {k:2}:${f({ k: 2 })}`);
function A(obj) {
for (var i in obj) return false;
return true;
}
function B(obj) {
return JSON.stringify(obj) === "{}";
}
function C(obj) {
return Object.keys(obj).length === 0;
}
function D(obj) {
return Object.entries(obj).length === 0;
}
function E(obj) {
return Object.getOwnPropertyNames(obj).length === 0;
}
function F(obj) {
return Object.keys(obj).length === 0 && obj.constructor === Object;
}
function G(obj) {
return typeof obj === "undefined" || !Boolean(Object.keys(obj)[0]);
}
function H(obj) {
return Object.entries(obj).length === 0 && obj.constructor === Object;
}
function I(obj) {
return Object.values(obj).every((val) => typeof val === "undefined");
}
function J(obj) {
for (const key in obj) {
if (hasOwnProperty.call(obj, key)) {
return false;
}
}
return true;
}
function K(obj) {
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) {
return false;
}
}
return JSON.stringify(obj) === JSON.stringify({});
}
function L(obj) {
for (var prop in obj) {
if (obj.hasOwnProperty(prop)) return false;
}
return true;
}
function M(obj) {
for (var k in obj) {
if (obj.hasOwnProperty(k)) {
return false;
}
}
return true;
}
function N(obj) {
return (
Object.getOwnPropertyNames(obj).length === 0 &&
Object.getOwnPropertySymbols(obj).length === 0 &&
Object.getPrototypeOf(obj) === Object.prototype
);
}
function O(obj) {
return !(Object.getOwnPropertyNames !== undefined
? Object.getOwnPropertyNames(obj).length !== 0
: (function () {
for (var key in obj) break;
return key !== null && key !== undefined;
})());
}
log("A", A);
log("B", B);
log("C", C);
log("D", D);
log("E", E);
log("F", F);
log("G", G);
log("H", H);
log("I", I);
log("J", J);
log("K", K);
log("L", L);
log("M", M);
log("N", N);
log("O", O);
You can use Underscore.js.
_.isEmpty({}); // true
if(Object.getOwnPropertyNames(obj).length === 0){
//is empty
}
see http://bencollier.net/2011/04/javascript-is-an-object-empty/
How about using JSON.stringify? It is almost available in all modern browsers.
function isEmptyObject(obj){
return JSON.stringify(obj) === '{}';
}
There is a simple way if you are on a newer browser.
Object.keys(obj).length === 0
Old question, but just had the issue. Including JQuery is not really a good idea if your only purpose is to check if the object is not empty. Instead, just deep into JQuery's code, and you will get the answer:
function isEmptyObject(obj) {
var name;
for (name in obj) {
if (obj.hasOwnProperty(name)) {
return false;
}
}
return true;
}
Using Object.keys(obj).length (as suggested above for ECMA 5+) is 10 times slower for empty objects! keep with the old school (for...in) option.
Tested under Node, Chrome, Firefox and IE 9, it becomes evident that for most use cases:
(for...in...) is the fastest option to use!
Object.keys(obj).length is 10 times slower for empty objects
JSON.stringify(obj).length is always the slowest (not suprising)
Object.getOwnPropertyNames(obj).length takes longer than Object.keys(obj).length can be much longer on some systems.
Bottom line performance wise, use:
function isEmpty(obj) {
for (var x in obj) { return false; }
return true;
}
or
function isEmpty(obj) {
for (var x in obj) { if (obj.hasOwnProperty(x)) return false; }
return true;
}
See detailed testing results and test code at Is object empty?
My take:
function isEmpty(obj) {
return Object.keys(obj).length === 0;
}
var a = {
a: 1,
b: 2
}
var b = {}
console.log(isEmpty(a)); // false
console.log(isEmpty(b)); // true
Just, I don't think all browsers implement Object.keys() currently.
I am using this.
function isObjectEmpty(object) {
var isEmpty = true;
for (keys in object) {
isEmpty = false;
break; // exiting since we found that the object is not empty
}
return isEmpty;
}
Eg:
var myObject = {}; // Object is empty
var isEmpty = isObjectEmpty(myObject); // will return true;
// populating the object
myObject = {"name":"John Smith","Address":"Kochi, Kerala"};
// check if the object is empty
isEmpty = isObjectEmpty(myObject); // will return false;
from here
Update
OR
you can use the jQuery implementation of isEmptyObject
function isEmptyObject(obj) {
var name;
for (name in obj) {
return false;
}
return true;
}
Just a workaround. Can your server generate some special property in case of no data?
For example:
var a = {empty:true};
Then you can easily check it in your AJAX callback code.
Another way to check it:
if (a.toSource() === "({})") // then 'a' is empty
EDIT:
If you use any JSON library (f.e. JSON.js) then you may try JSON.encode() function and test the result against empty value string.
1. Using Object.keys
Object.keys will return an Array, which contains the property names of the object. If the length of the array is 0, then we know that the object is empty.
function isEmpty(obj) {
return Object.keys(obj).length === 0 && obj.constructor === Object;
}
We can also check this using Object.values and Object.entries.
This is typically the easiest way to determine if an object is empty.
2. Looping over object properties with for…in
The for…in statement will loop through the enumerable property of object.
function isEmpty(obj) {
for(var prop in obj) {
if(obj.hasOwnProperty(prop))
return false;
}
return true;
}
In the above code, we will loop through object properties and if an object has at least one property, then it will enter the loop and return false. If the object doesn’t have any properties then it will return true.
#3. Using JSON.stringify
If we stringify the object and the result is simply an opening and closing bracket, we know the object is empty.
function isEmptyObject(obj){
return JSON.stringify(obj) === '{}';
}
4. Using jQuery
jQuery.isEmptyObject(obj);
5. Using Underscore and Lodash
_.isEmpty(obj);
Resource
function isEmpty(obj) {
for(var i in obj) { return false; }
return true;
}
The following example show how to test if a JavaScript object is empty, if by empty we means has no own properties to it.
The script works on ES6.
const isEmpty = (obj) => {
if (obj === null ||
obj === undefined ||
Array.isArray(obj) ||
typeof obj !== 'object'
) {
return true;
}
return Object.getOwnPropertyNames(obj).length === 0;
};
console.clear();
console.log('-----');
console.log(isEmpty('')); // true
console.log(isEmpty(33)); // true
console.log(isEmpty([])); // true
console.log(isEmpty({})); // true
console.log(isEmpty({ length: 0, custom_property: [] })); // false
console.log('-----');
console.log(isEmpty('Hello')); // true
console.log(isEmpty([1, 2, 3])); // true
console.log(isEmpty({ test: 1 })); // false
console.log(isEmpty({ length: 3, custom_property: [1, 2, 3] })); // false
console.log('-----');
console.log(isEmpty(new Date())); // true
console.log(isEmpty(Infinity)); // true
console.log(isEmpty(null)); // true
console.log(isEmpty(undefined)); // true
The correct answer is:
function isEmptyObject(obj) {
return (
Object.getPrototypeOf(obj) === Object.prototype &&
Object.getOwnPropertyNames(obj).length === 0 &&
Object.getOwnPropertySymbols(obj).length === 0
);
}
This checks that:
The object's prototype is exactly Object.prototype.
The object has no own properties (regardless of enumerability).
The object has no own property symbols.
In other words, the object is indistinguishable from one created with {}.
jQuery have special function isEmptyObject() for this case:
jQuery.isEmptyObject({}) // true
jQuery.isEmptyObject({ foo: "bar" }) // false
Read more on http://api.jquery.com/jQuery.isEmptyObject/
Caveat! Beware of JSON's limitiations.
javascript:
obj={ f:function(){} };
alert( "Beware!! obj is NOT empty!\n\nobj = { f:function(){} }" +
"\n\nJSON.stringify( obj )\n\nreturns\n\n" +
JSON.stringify( obj ) );
displays
Beware!! obj is NOT empty!
obj = { f:function(){} }
JSON.stringify( obj )
returns
{}
To really accept ONLY {}, the best way to do it in Javascript using Lodash is:
_.isEmpty(value) && _.isPlainObject(value)
In addition to Thevs answer:
var o = {};
alert($.toJSON(o)=='{}'); // true
var o = {a:1};
alert($.toJSON(o)=='{}'); // false
it's jquery + jquery.json
Sugar.JS provides extended objects for this purpose. The code is clean and simple:
Make an extended object:
a = Object.extended({})
Check it's size:
a.size()
Pure Vanilla Javascript, and full backward compatibility
function isObjectDefined (Obj) {
if (Obj === null || typeof Obj !== 'object' ||
Object.prototype.toString.call(Obj) === '[object Array]') {
return false
} else {
for (var prop in Obj) {
if (Obj.hasOwnProperty(prop)) {
return true
}
}
return JSON.stringify(Obj) !== JSON.stringify({})
}
}
console.log(isObjectDefined()) // false
console.log(isObjectDefined('')) // false
console.log(isObjectDefined(1)) // false
console.log(isObjectDefined('string')) // false
console.log(isObjectDefined(NaN)) // false
console.log(isObjectDefined(null)) // false
console.log(isObjectDefined({})) // false
console.log(isObjectDefined([])) // false
console.log(isObjectDefined({a: ''})) // true
IsEmpty Object, unexpectedly lost its meaning i.e.: it's programming semantics, when our famous guru from Yahoo introduced the customized non-enumerable Object properties to ECMA and they got accepted.
[ If you don't like history - feel free to skip right to the working code ]
I'm seeing lots of good answers \ solutions to this question \ problem.
However, grabbing the most recent extensions to ECMA Script is not the honest way to go. We used to hold back the Web back in the day to keep Netscape 4.x, and Netscape based pages work and projects alive, which (by the way) were extremely primitive backwards and idiosyncratic, refusing to use new W3C standards and propositions [ which were quite revolutionary for that time and coder friendly ] while now being brutal against our own legacy.
Killing Internet Explorer 11 is plain wrong! Yes, some old warriors that infiltrated Microsoft remaining dormant since the "Cold War" era, agreed to it - for all the wrong reasons. - But that doesn't make it right!
Making use, of a newly introduced method\property in your answers and handing it over as a discovery ("that was always there but we didn't notice it"), rather than a new invention (for what it really is), is somewhat 'green' and harmful. I used to make such mistakes some 20 years ago when I still couldn't tell what's already in there and treated everything I could find a reference for, as a common working solution...
Backward compatibility is important !
We just don't know it yet. That's the reason I got the need to share my 'centuries old' generic solution which remains backward and forward compatible to the unforeseen future.
There were lots of attacks on the in operator but I think the guys doing that have finally come to senses and really started to understand and appreciate a true Dynamic Type Language such as JavaScript and its beautiful nature.
My methods aim to be simple and nuclear and for reasons mentioned above, I don't call it "empty" because the meaning of that word is no longer accurate. Is Enumerable, seems to be the word with the exact meaning.
function isEnum( x ) { for( var p in x )return!0; return!1 };
Some use cases:
isEnum({1:0})
true
isEnum({})
false
isEnum(null)
false
Thanks for reading!
Best one-liner solution I could find (updated):
isEmpty = obj => !Object.values(obj).filter(e => typeof e !== 'undefined').length;
console.log(isEmpty({})) // true
console.log(isEmpty({a: undefined, b: undefined})) // true
console.log(isEmpty({a: undefined, b: void 1024, c: void 0})) // true
console.log(isEmpty({a: [undefined, undefined]})) // false
console.log(isEmpty({a: 1})) // false
console.log(isEmpty({a: ''})) // false
console.log(isEmpty({a: null, b: undefined})) // false
Another alternative is to use is.js (14kB) as opposed to jquery (32kB), lodash (50kB), or underscore (16.4kB). is.js proved to be the fastest library among aforementioned libraries that could be used to determine whether an object is empty.
http://jsperf.com/check-empty-object-using-libraries
Obviously all these libraries are not exactly the same so if you need to easily manipulate the DOM then jquery might still be a good choice or if you need more than just type checking then lodash or underscore might be good. As for is.js, here is the syntax:
var a = {};
is.empty(a); // true
is.empty({"hello": "world"}) // false
Like underscore's and lodash's _.isObject(), this is not exclusively for objects but also applies to arrays and strings.
Under the hood this library is using Object.getOwnPropertyNames which is similar to Object.keys but Object.getOwnPropertyNames is a more thorough since it will return enumerable and non-enumerable properties as described here.
is.empty = function(value) {
if(is.object(value)){
var num = Object.getOwnPropertyNames(value).length;
if(num === 0 || (num === 1 && is.array(value)) || (num === 2 && is.arguments(value))){
return true;
}
return false;
} else {
return value === '';
}
};
If you don't want to bring in a library (which is understandable) and you know that you are only checking objects (not arrays or strings) then the following function should suit your needs.
function isEmptyObject( obj ) {
return Object.getOwnPropertyNames(obj).length === 0;
}
This is only a bit faster than is.js though just because you aren't checking whether it is an object.
I know this doesn't answer 100% your question, but I have faced similar issues before and here's how I use to solve them:
I have an API that may return an empty object. Because I know what fields to expect from the API, I only check if any of the required fields are present or not.
For example:
API returns {} or {agentID: '1234' (required), address: '1234 lane' (opt),...}.
In my calling function, I'll only check
if(response.data && response.data.agentID) {
do something with my agentID
} else {
is empty response
}
This way I don't need to use those expensive methods to check if an object is empty. The object will be empty for my calling function if it doesn't have the agentID field.
We can check with vanilla js with handling null or undefined check also as follows,
function isEmptyObject(obj) {
return !!obj && Object.keys(obj).length === 0 && obj.constructor === Object;
}
//tests
isEmptyObject(new Boolean()); // false
isEmptyObject(new Array()); // false
isEmptyObject(new RegExp()); // false
isEmptyObject(new String()); // false
isEmptyObject(new Number()); // false
isEmptyObject(new Function()); // false
isEmptyObject(new Date()); // false
isEmptyObject(null); // false
isEmptyObject(undefined); // false
isEmptyObject({}); // true
I liked this one I came up with, with the help of some other answers here. Thought I'd share it.
Object.defineProperty(Object.prototype, 'isEmpty', {
get() {
for(var p in this) {
if (this.hasOwnProperty(p)) {return false}
}
return true;
}
});
let users = {};
let colors = {primary: 'red'};
let sizes = {sm: 100, md: 200, lg: 300};
console.log(
'\nusers =', users,
'\nusers.isEmpty ==> ' + users.isEmpty,
'\n\n-------------\n',
'\ncolors =', colors,
'\ncolors.isEmpty ==> ' + colors.isEmpty,
'\n\n-------------\n',
'\nsizes =', sizes,
'\nsizes.isEmpty ==> ' + sizes.isEmpty,
'\n',
''
);
It's weird that I haven't encountered a solution that compares the object's values as opposed to the existence of any entry (maybe I missed it among the many given solutions).
I would like to cover the case where an object is considered empty if all its values are undefined:
const isObjectEmpty = obj => Object.values(obj).every(val => typeof val === "undefined")
console.log(isObjectEmpty({})) // true
console.log(isObjectEmpty({ foo: undefined, bar: undefined })) // true
console.log(isObjectEmpty({ foo: false, bar: null })) // false
Example usage
Let's say, for the sake of example, you have a function (paintOnCanvas) that destructs values from its argument (x, y and size). If all of them are undefined, they are to be left out of the resulting set of options. If not they are not, all of them are included.
function paintOnCanvas ({ brush, x, y, size }) {
const baseOptions = { brush }
const areaOptions = { x, y, size }
const options = isObjectEmpty(areaOptions) ? baseOptions : { ...baseOptions, areaOptions }
// ...
}
I know this has been an issue for a while now, and checked all previously answers I could get, but still this one doesn't work.
The object 'crew' represents crewmembers with ranks and other items. The comparison should be made by comparing 'assigned_rank', an int value, and if this value is equal in both instances, then 'is_trainer', a boolean, should make the difference.
This method worked great as long as it was running with java < 7. But since Java 7 I keep getting this one:
java.lang.IllegalArgumentException: Comparison method violates its general contract!
at java.util.ComparableTimSort.mergeLo(ComparableTimSort.java:714)
at java.util.ComparableTimSort.mergeAt(ComparableTimSort.java:451)
at java.util.ComparableTimSort.mergeCollapse(ComparableTimSort.java:376)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:182)
at java.util.ComparableTimSort.sort(ComparableTimSort.java:146)
at java.util.Arrays.sort(Arrays.java:472)
at java.util.Collections.sort(Collections.java:155)
at dormas_flightlog.Query.getCrew(Query.java:714)
Here is the source, where some potentially dangerous parts have allready been out-commented, but it still does not work:
public class crew implements Serializable, Comparable<crew> {
private static final long serialVersionUID = 36L;
private int flightID = 0;
private int assigned_rank = 25;
private boolean is_trainer = false;
...
#Override
public int compareTo(crew him) {
int myRank = this.getAssigned_rank();
int hisRank = him.assigned_rank;
if (this == him) {
return 0;
}
if (myRank > hisRank) {
return 1;
}
if (myRank < hisRank) {
return -1;
}
if (myRank == hisRank) {
// if (is_trainer && !o.is_trainer) {
// i = 1;
// }
// if (!is_trainer && o.is_trainer) {
// i = -1;
// }
// if (is_trainer && o.is_trainer) {
// i = 0;
// }
// if (!is_trainer && !o.is_trainer) {
// i = 0;
// }
return 0;
}
return 0;
}
#Override
public int hashCode() {
int hash = 7;
hash = 31 * hash + this.assigned_rank;
hash = 31 * hash + (this.is_trainer ? 1 : 0);
return hash;
}
#Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
int myRank = this.getAssigned_rank();
int hisRank = 0;
if (o instanceof crew) {
crew him = (crew) o;
hisRank = him.assigned_rank;
} else {
return false;
}
if (myRank > hisRank) {
return false;
}
if (myRank < hisRank) {
return false;
}
if (myRank == hisRank) {
// if (is_trainer && !o.is_trainer) {
// i = 1;
// }
// if (!is_trainer && o.is_trainer) {
// i = -1;
// }
// if (is_trainer && o.is_trainer) {
// i = 0;
// }
// if (!is_trainer && !o.is_trainer) {
// i = 0;
// }
return true;
}
return false;
}
}
Implementing equals() was just a try to solve this problem. The given exception comes with or without equals(). I cannot see how the compareTo-method violates its contract. Any help is greatly appreciated....one day this code has to work with java 7 and I don't know how...
Thanks
see this:
From http://www.oracle.com/technetwork/java/javase/compatibility-417013.html#source
Area: API: Utilities Synopsis: Updated sort behavior for Arrays and
Collections may throw an IllegalArgumentException
Description: The sorting algorithm used by java.util.Arrays.sort and
(indirectly) by java.util.Collections.sort has been replaced. The new
sort implementation may throw an IllegalArgumentException if it detects
a Comparable that violates the Comparable contract. The previous
implementation silently ignored such a situation. If the previous
behavior is desired, you can use the new system
property java.util.Arrays.useLegacyMergeSort, to restore previous
mergesort behavior.
Nature of Incompatibility: behavioral
RFE: 6804124
For more detailed info, see the bug database reference here.
maybe you just have NaN values which you compare through Collections.sort(...), this has been a problem to me and I got that exception even having right implementation of compare(obj1, obj2) method! Check that!
I was able to solve this error cause it was a bug in jdk7.
here I found the solution:
"Comparison method violates its general contract!" - TimSort and GridLayout
Basically i just had to add the
JAVA_OPTS="$JAVA_OPTS -Djava.util.Arrays.useLegacyMergeSort=true"
to my jboss
Unfortunately, none of the solutions work for Android. TimSort is used deep in Android's ViewGroup relating to addChildrenForAccessibility that shows up under Java 7 & 8. No user code is involved in any comparison.
From other reports, it is related to having RelativeLayout with overlapping items as is commonly done. For example, a TextView that appears over an Image, or two items at the same location, where you only set one visible at a time.
https://code.google.com/p/android/issues/detail?id=55933
I've not found any way around the bug. You can't set a -Djava option in Android Studio or Eclipse (at least that I could find). Forcing use of Java 1.6 should work, but doesn't. Seems like Amazon's newer Fire tablets and phones are far more sensitive to this bug than other devices.
There are rumors Java 9 will have a fix such as a run-time option that works, but with a bug that's been around for years, I have doubts it will ever be fixed - especially considering the animosity between Oracle and Google. Any yes, perhaps the bug is really deep in the Android code and should be fixed there. With more than a billion devices out there, that's not a viable solution for all the existing devices.
I am getting some errors thrown in my code when I open a Windows Forms form in Visual Studio's designer. I would like to branch in my code and perform a different initialization if the form is being opened by designer than if it is being run for real.
How can I determine at run-time if the code is being executed as part of designer opening the form?
if (System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime)
{
// Design time logic
}
To find out if you're in "design mode":
Windows Forms components (and controls) have a DesignMode property.
Windows Presentation Foundation controls should use the IsInDesignMode attached property.
The Control.DesignMode property is probably what you're looking for. It tells you if the control's parent is open in the designer.
In most cases it works great, but there are instances where it doesn't work as expected. First, it doesn't work in the controls constructor. Second, DesignMode is false for "grandchild" controls. For example, DesignMode on controls hosted in a UserControl will return false when the UserControl is hosted in a parent.
There is a pretty easy workaround. It goes something like this:
public bool HostedDesignMode
{
get
{
Control parent = Parent;
while (parent!=null)
{
if(parent.DesignMode) return true;
parent = parent.Parent;
}
return DesignMode;
}
}
I haven't tested that code, but it should work.
The most reliable approach is:
public bool isInDesignMode
{
get
{
System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess();
bool res = process.ProcessName == "devenv";
process.Dispose();
return res;
}
}
The most reliable way to do this is to ignore the DesignMode property and use your own flag that gets set on application startup.
Class:
public static class Foo
{
public static bool IsApplicationRunning { get; set; }
}
Program.cs:
[STAThread]
static void Main()
{
Foo.IsApplicationRunning = true;
// ... code goes here ...
}
Then just check the flag whever you need it.
if(Foo.IsApplicationRunning)
{
// Do runtime stuff
}
else
{
// Do design time stuff
}
I had the same problem in Visual Studio Express 2013. I tried many of the solutions suggested here but the one that worked for me was an answer to a different thread, which I will repeat here in case the link is ever broken:
protected static bool IsInDesigner
{
get { return (Assembly.GetEntryAssembly() == null); }
}
The devenv approach stopped working in VS2012 as the designer now has its own process. Here is the solution I am currently using (the 'devenv' part is left there for legacy, but without VS2010 I am not able to test that though).
private static readonly string[] _designerProcessNames = new[] { "xdesproc", "devenv" };
private static bool? _runningFromVisualStudioDesigner = null;
public static bool RunningFromVisualStudioDesigner
{
get
{
if (!_runningFromVisualStudioDesigner.HasValue)
{
using (System.Diagnostics.Process currentProcess = System.Diagnostics.Process.GetCurrentProcess())
{
_runningFromVisualStudioDesigner = _designerProcessNames.Contains(currentProcess.ProcessName.ToLower().Trim());
}
}
return _runningFromVisualStudioDesigner.Value;
}
}
/// <summary>
/// Are we in design mode?
/// </summary>
/// <returns>True if in design mode</returns>
private bool IsDesignMode() {
// Ugly hack, but it works in every version
return 0 == String.CompareOrdinal(
"devenv.exe", 0,
Application.ExecutablePath, Application.ExecutablePath.Length - 10, 10);
}
System.Diagnostics.Debugger.IsAttached
It's hack-ish, but if you're using VB.NET and when you're running from within Visual Studio My.Application.Deployment.CurrentDeployment will be Nothing, because you haven't deployed it yet. I'm not sure how to check the equivalent value in C#.
using (System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess())
{
bool inDesigner = process.ProcessName.ToLower().Trim() == "devenv";
return inDesigner;
}
I tried the above code (added a using statement) and this would fail on some occasions for me. Testing in the constructor of a usercontrol placed directly in a form with the designer loading at startup. But would work in other places.
What worked for me, in all locations is:
private bool isDesignMode()
{
bool bProcCheck = false;
using (System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess())
{
bProcCheck = process.ProcessName.ToLower().Trim() == "devenv";
}
bool bModeCheck = (System.ComponentModel.LicenseManager.UsageMode == System.ComponentModel.LicenseUsageMode.Designtime);
return bProcCheck || DesignMode || bModeCheck;
}
Maybe a bit overkill, but it works, so is good enough for me.
The success in the example noted above is the bModeCheck, so probably the DesignMode is surplus.
You check the DesignMode property of your control:
if (!DesignMode)
{
//Do production runtime stuff
}
Note that this won't work in your constructor because the components haven't been initialized yet.
When running a project, its name is appended with ".vshost".
So, I use this:
public bool IsInDesignMode
{
get
{
Process p = Process.GetCurrentProcess();
bool result = false;
if (p.ProcessName.ToLower().Trim().IndexOf("vshost") != -1)
result = true;
p.Dispose();
return result;
}
}
It works for me.
I'm not sure if running in debug mode counts as real, but an easy way is to include an if statement in your code that checkes for System.Diagnostics.Debugger.IsAttached.
If you created a property that you don't need at all at design time, you can use the DesignerSerializationVisibility attribute and set it to Hidden. For example:
protected virtual DataGridView GetGrid()
{
throw new NotImplementedException("frmBase.GetGrid()");
}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public int ColumnCount { get { return GetGrid().Columns.Count; } set { /*Some code*/ } }
It stopped my Visual Studio crashing every time I made a change to the form with NotImplementedException() and tried to save. Instead, Visual Studio knows that I don't want to serialize this property, so it can skip it. It only displays some weird string in the properties box of the form, but it seems to be safe to ignore.
Please note that this change does not take effect until you rebuild.
We use the following code in UserControls and it does the work. Using only DesignMode will not work in your app that uses your custom user controls as pointed out by other members.
public bool IsDesignerHosted
{
get { return IsControlDesignerHosted(this); }
}
public bool IsControlDesignerHosted(System.Windows.Forms.Control ctrl)
{
if (ctrl != null)
{
if (ctrl.Site != null)
{
if (ctrl.Site.DesignMode == true)
return true;
else
{
if (IsControlDesignerHosted(ctrl.Parent))
return true;
else
return false;
}
}
else
{
if (IsControlDesignerHosted(ctrl.Parent))
return true;
else
return false;
}
}
else
return false;
}
Basically the logic above boils down to:
public bool IsControlDesignerHosted(System.Windows.Forms.Control ctrl)
{
if (ctrl == null) return false;
if (ctrl.Site != null && ctrl.Site.DesignMode) return true;
return IsControlDesignerHosted(ctrl.Parent);
}
If you are in a form or control you can use the DesignMode property:
if (DesignMode)
{
DesignMode Only stuff
}
I found the DesignMode property to be buggy, at least in previous versions of Visual Studio. Hence, I made my own using the following logic:
Process.GetCurrentProcess().ProcessName.ToLower().Trim() == "devenv";
Kind of a hack, I know, but it works well.
System.ComponentModel.Component.DesignMode == true
To solve the problem, you can also code as below:
private bool IsUnderDevelopment
{
get
{
System.Diagnostics.Process process = System.Diagnostics.Process.GetCurrentProcess();
if (process.ProcessName.EndsWith(".vshost")) return true;
else return false;
}
}
Here's another one:
//Caters only to thing done while only in design mode
if (App.Current.MainWindow == null){ // in design mode }
//Avoids design mode problems
if (App.Current.MainWindow != null) { //applicaiton is running }
After testing most of the answers here, unfortunately nothing worked for me (VS2015).
So I added a little twist to JohnV's answer, which didn't work out of the box, since DesignMode is a protected Property in the Control class.
First I made an extension method which returns the DesignMode's Property value via Reflection:
public static Boolean GetDesignMode(this Control control)
{
BindingFlags bindFlags = BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Static;
PropertyInfo prop = control.GetType().GetProperty("DesignMode", bindFlags);
return (Boolean)prop.GetValue(control, null);
}
and then I made a function like JohnV:
public bool HostedDesignMode
{
get
{
Control parent = Parent;
while (parent != null)
{
if (parent.GetDesignMode()) return true;
parent = parent.Parent;
}
return DesignMode;
}
}
This is the only method that worked for me, avoiding all the ProcessName mess, and while reflection should not be used lightly, in this case it did all the difference! ;)
EDIT:
You can also make the second function an extension method like this:
public static Boolean IsInDesignMode(this Control control)
{
Control parent = control.Parent;
while (parent != null)
{
if (parent.GetDesignMode())
{
return true;
}
parent = parent.Parent;
}
return control.GetDesignMode();
}
For WPF (hopefully this is useful for those WPF people stumbling upon this question):
if (System.ComponentModel.DesignerProperties.GetIsInDesignMode(new DependencyObject()))
{
}
GetIsInDesignMode requires a DependencyObject. If you don't have one, just create one.
/// <summary>
/// Whether or not we are being run from the Visual Studio IDE
/// </summary>
public bool InIDE
{
get
{
return Process.GetCurrentProcess().ProcessName.ToLower().Trim().EndsWith("vshost");
}
}
Here's a flexible way that is adaptable to where you compile from as well as whether or not you care which mode you're in.
string testString1 = "\\bin\\";
//string testString = "\\bin\\Debug\\";
//string testString = "\\bin\\Release\\";
if (AppDomain.CurrentDomain.BaseDirectory.Contains(testString))
{
//Your code here
}