I get an infinite loop if the URL contains bad data.
This URL asks to see an ID-related list but provides a bad ID
<siteroot>/<client>/Class/Index/-1
I detect that bad ID and do RedirectToAction("Index") which, without an ID, should show a generic list instead. But when the redirect is routed, the bad ID is still there!
Note the ID is optional for the Index method public ActionResult Index(int? id, int? yid)
Thanks,
Eric
Explicitly pass a null value for id in the redirect
int? badId = null;
return RedirectToAction("Index", new {id = badId});
You can't assign id = null directly in the anonymous route value object, so you need the preceding line to set id to null. I don't know what yid is, but you may need to expicitly set that as well, lest the bad id fall into that parameter.
Related
Being new to attribute routing, I'd like to ask for help getting this to work.
This test is a simple dynamic DB table viewer: Given a table name (or stored query name or whatever) and optionally some WHERE parameters, return query results.
Table COMPANIES (one of any number of tables which has an associated SELECT query stored somewhere, keyed by table name):
ID NAME HQ INDUSTRY
1 Apple USA Consumer electronics
2 Bose USA Low-quality, expensive audio equipment
3 Nokia FIN Mobile Phones
Controller:
[Route("view/{table}/{parameters}")]
public object Get(string table, Dictionary<string, string> parameters) {
var sql = GetSql(table);
var dbArgs = new DynamicParameters(parameters);
return Database.Query(sql, dbArgs); // Return stuff/unrelated to problem
}
SQL stored in some resource or table. Obviously the parameters must match exactly:
SELECT * FROM companies
WHERE name = :name
-- OR hq = :hq
-- OR ...etc. Doesn't matter since it never gets this far.
Request (Should look clean, but the exact URL format isn't important):
www.website.com/view/companies?hq=fin --> 404: No matching controller
www.website.com/view/companies/hq=fin --> parameters is null
www.website.com/view/companies/hq=fin&name=nokia --> Exception: A potentially dangerous Request.Path value was detected from the client (&).
When I use: [Route("view/{table}{parameters}")] I get:
A path segment cannot contain two consecutive parameters. They must be separated by a '/' or by a literal string. Parameter name: routeTemplate. Makes sense.
My question is: How do I accept a table name and any number of unknown parameters in the usual key1=val1&key2=val2 form (not some awkward indexed format like the one mentioned here) which will be later bound to SQL parameters, preferably using a vanilla data structure rather than something like FormCollection.
I don't think that binding URL parameters to a Dictionary is built-in to the framework. I'm sure there's a way to extend it if you wanted to.
I think quickest (but still acceptable) option is to get the query string parameters using Request.GetQueryNameValuePairs() like this:
[Route("view/{table}")]
public object Get(string table) {
Dictionary<string, string> parameters = Request.GetQueryNameValuePairs()
.ToDictionary(x => x.Key, x => x.Value);
var sql = GetSql(table);
var dbArgs = new DynamicParameters(parameters);
return Database.Query(sql, dbArgs); // Return stuff/unrelated to problem
}
I'm using MVC3 .NET4.0 (VB), and I'm seeing some strange behavior on a simple View. It's a Create view that is set up as:
Inherits="System.Web.Mvc.ViewPage(Of MyProject.MyTable)
The controller is pretty straightforward. It accepts the ID of the parent record to which this record is being added:
Function Create(parent As Integer) As ActionResult
Return View(New MyTable With {.parent_id = parent})
End Function
The View also accepts a date among other things, but it boils down to this:
<% Using Html.BeginForm()%>
<%=Html.ValidationSummary(True)%>
<%=Html.DisplayFor(Function(model) model.parent_id)%>
<%=Html.TextBoxFor(Function(model) model.start_date)%>
<%=Html.ValidationMessageFor(Function(model) model.start_date, "*")%>
<button type="submit" id="submitButton">Save</button>
<% End Using%>
I'm testing the handling of date errors, so right now my post controller is just checking for errors and not doing much else:
<HttpPost()>
Function Create(model As MyTable) As ActionResult
If ModelState.IsValid Then
Return RedirectToAction("Index")
Else
Return View(model)
End If
End Function
When I first load the view, I see the parent ID displayed on the form. If I put a bad date into the start date field and hit Submit, the form comes back with the invalid value highlighted, but the parent ID = 0. If I break the code in the post, I can see that "model" doesn't have the parent ID set. This obviously causes all kinds of problems, because I've essentially lost who the parent is. What am I doing wrong?
UPDATE
Per Darin's suggestion I changed DisplayFor to HiddenFor and didn't see any difference. So then I tried TextBoxFor and got stranger results. I still don't see the parent ID in the post function, but the value persists in the text box.
What am I doing wrong?
You are not including the parent_id as hidden field in your form. Inside your form you have a single input element which corresponds to the start_date field, so that's all that you can hope to get in your POST action.
So:
<%= Html.HiddenFor(Function(model) model.parent_id) %>
The DisplayFor that you used only displays the value, it doesn't emit any input field to transport this value to the server when the form is submitted.
I have created a structure and list.
public struct CarMake
{
public string name;
public string id;
}
I added structure objects to this (carMakers) and am trying to query
string selCar = from c in carMakers
where c.name == selectedCarMfgName
select c.id;
I am getting an error near select statement- cannont implicity convert IEnumerable to string. I know that query returns only one value, that's why I have like that.
thanks !
string selCar = (from c in carMakers
where c.name == selectedCarMfgName
select c.id).SingleOrDefault();
Your query returns a collection (with one element). You should use Single() (or SingleOrDefault()) to get that one item. If the query can return more than one result, you should look into First() ( or FirstOrDefault())
Pay attention to the error message. It probably says something like
"cannot implicitly convert IEnumerable<string> to string."
The results of a query of a sequence is another sequence, an IEnumerable<T>. You may know that you expect only one result, but that's not what the query does. To obtain only one result, you can optionally include another extension method on the end.
yourQuery.First();
yourQuery.FirstOrDefault();
yourQuery.Single();
yourQuery.SingleOrDefault();
The difference in these is that the First* variations can work with sequenes with many elements, whereas the Single* variations will throw exceptions if more than one element is present. The *OrDefault variations support the concept of no matching elements, and returns the default value for the type (null in the case of classes, a default value (such as 0 for int) for structs).
Use the version that conforms to your expectation. If you expect one and only one match, prefer Single. If you only care about one out of arbitrarily many, prefer First.
carMakers.Add(new CarMake() { name = "Audi", id = "1234" });
string selCar =(from c in carMakers
where c.name == "Audi"
select c.id).FirstOrDefault();
Output- 1234
I would refactor my query slightly:
var selCar = carMakers.Single(c => c.name == selectedCarMfgName).id;
This assumes you know that the car is in the list. If not, use SingleOrDefault and check the return before getting the id.
I've not done too much with LINQ but because you are selecting into a string you may need to use FirstOrDefault as your statement could return back more than one value yet your string can only hold one.
First will return null value I think if nothing is found but FirstOrDefault will return you a blank string.
I have a stored proc that returns a list of users (rows in User table).
var admins = db.aspnet_UsersInRoles_GetUsersInRoles('/', "Admin");
LINQ generated aspnet_User classes for me, so can I somehow map the result to a List of aspnet_User type? Something like:
List<aspnet_User> admins = db.aspnet_UsersInRoles_GetUsersInRoles('/', "Admin");
Here is a capture of what is returned.
It's entirely possible that you just need:
List<aspnet_User> admins = db.aspnet_UsersInRoles_GetUsersInRoles('/', "Admin")
.ToList();
But it's hard to know without seeing what type the method call returns.
Perhaps this should be a comment but it is way too long...
Well, you do not really want the internal class <aspnet_User> you should want a MembershipUser.
So how about not using the stored procedure that comes with the membership provider but really use the Membership provider itsself.
There is a beautiful class: Roles in System.Web.Security
And it gives you this:
public static string[] GetUsersInRole(string roleName)
From here, a foreach to get the MembershipUser(s) in a list is not that complicated.
By default a stored procedure will return a type that it determines based on the output columns with Result tacked on to the end. It doesn't associate it with types you have already determined. To change this, you can either change the Return Type in the property window to the type you have already defined in your model, or when dragging the stored proc into your model, drop it directly on the type that you want the stored proc to be mapped into.
You don't get the opportunity to change the column mappings for stored procs however, so make sure the shape that the stored proc generates is the same as your target object structures.
It's an old post and I was working on it today and I get the same issue,
I think you are requesting asp membership ?
You can not convert this stored procedure to aspnet_User because it returns aspnet_UsersInRoles_GetUsersInRolesResult type.
but from this aspnet_UsersInRoles_GetUsersInRolesResult you can get userName, then request the aspnet_User table:
String app = "your application name";
String role = "your role name";
ArrayList userInRoleList = new ArrayList();
//Get the role ID
ASPNETDBDataContext aspDB = new ASPNETDBDataContext();
var userInRole = aspDB.aspnet_UsersInRoles_GetUsersInRoles(app, role);
foreach (aspnet_UsersInRoles_GetUsersInRolesResult users in userInRole)
{
userInRoleList.Add(users.UserName);
}
I'm using a Typed DataSet with an Insert statement; I have a table that has a smalldatetime field defined to accept null values. When I insert from a .NET 2.0 FormView, I get a "SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM."
Now, I've read this post, and the parameter as sent to the class constructor is defined as
global::System.Nullable<global::System.DateTime> DoB
So, it looks like it should accept a Nullable obj. Additionally, the generated code is testing the value sent.
if ((DoB.HasValue == true)) {
command.Parameters[6].Value = ((System.DateTime)(DoB.Value));
}
else {
command.Parameters[6].Value = global::System.DBNull.Value;
}
Specifically, the error is occurring when generated SqlClient.SqlCommand.ExecuteScalar() runs:
try {
returnValue = command.ExecuteScalar();
}
So, I guess my question is: how do I use a Typed DataSet to set a blank value (passed from a FormView on CommandName=Insert) to a null in a database?
Ok, so here's what worked for me. First, to reiterate, I've got a Typed DataSet with DataAdapters that's generating the ADO objects. So, on my page, I can create a ObjectDataSource with the type that points to my adapter, and then name the different access methods housed there-in.
No, I have an Insert to a table where basically all the columns are nullable; some varchar, some smalldatetime.
When I submit an empty form, I'd like nulls to be entered. They're not and lots of various errors are thrown. What I ended up doing is subclassing the ObjectDataSource to gain access to the Inserting event. (subclassed for reusability) In the Inserting event, I looped through the InputParameters, and if it was a string and == "", I set it to null. Also, you cannot set ConvertNullToDBNull to true; that causes the strings to fail. This successfully allowed the Nullable to remain null.