gridview_new is a form class
private checkNulls[] CheckNulls()
{
checkNulls Cntrl;
checkNulls[] cntrlsToupdate = new checkNulls[15];
using (gridview_new IterateThroughCntrls = new gridview_new())
{
for (int i = 5; i < 18; i++)
{
var getCntrl =
IterateThroughCntrls.Controls.Cast<Control>().Where(x => x.TabIndex == i).SingleOrDefault();
if (!(getCntrl.Text == ""))
{
Cntrl = (checkNulls)(i);
cntrlsToupdate[i - 5] = Cntrl;
}
}
}
return cntrlsToupdate;
}
Get Control is getting a null value even though there is a control at tab-index 5.
First, ...OrDefault returns the default value for a given type, in case of reference types (like Control) you get null. So then you could simply check that:
if(getCntrl != null)
{
// safe....
}
If you want the text of the control and "" as default if the Where has found no matching controls, use Select + DefaultIfEmpty:
string getCntrlText = IterateThroughCntrls.Controls.Cast<Control>()
.Where(x => x.TabIndex == i)
.Select(ctrl => ctrl.Text)
.DefaultIfEmpty("")
.Single();
Note that i've used Single since i've provided a default value.
Note that Single... throws an exception (as opposed to First...) if multiple items match the predicate. Normally it's used with key properties where it should be impossible to find multiple elments. So First(or FirstOrDefault) seems to be more appropriate here.
Related
I am trying to build a search predicate in code that compares two fields in Sitecore and I am getting a strange error message. Basically I have two date fields on each content item - FirstPublishDate (the date that the content item was first published) and LastPublishDate (the last date that the content item was published). I would like to find all content items where the LastPublishDate falls within a certain date range AND where the LastPublishDate does not equal the FirstPublishDate. Using Linq here is my method for generating the predicate...
protected Expression<Func<T, Boolean>> getDateFacetPredicate<T>() where T : MySearchResultItem
{
var predicate = PredicateBuilder.True<T>();
foreach (var facet in myFacetCategories)
{
var dateTo = System.DateTime.Now;
var dateFrom = dateTo.AddDays(facet.Value*-1);
predicate = predicate.And(i => i.LastPublishDate.Between(dateFrom, dateTo, Inclusion.Both)).And(j => j.LastPublishDate != j.FirstPublishDate);
}
return predicate;
}
Then I use this predicate in my general site search code to perform the search as follows: the above predicate gets passed in to this method as the "additionalWhere" parameter.
public static SearchResults<T> GeneralSearch<T>(string searchText, ISearchIndex index, int currentPage = 0, int pageSize = 20, string language = "", IEnumerable<string> additionalFields = null,
Expression<Func<T, Boolean>> additionalWhere = null, Expression<Func<T, Boolean>> additionalFilter = null, IEnumerable<string> facets = null,
Expression<Func<T, Boolean>> facetFilter = null, string sortField = null, SortDirection sortDirection = SortDirection.Ascending) where T : SearchResultItem {
using (var context = index.CreateSearchContext()) {
var query = context.GetQueryable<T>();
if (!string.IsNullOrWhiteSpace(searchText)) {
var keywordPred = PredicateBuilder.True<T>();
// take into account escaping of special characters and working around Sitecore limitation with Contains and Equals methods
var isSpecialMatch = Regex.IsMatch(searchText, "[" + specialSOLRChars + "]");
if (isSpecialMatch) {
var wildcardText = string.Format("\"*{0}*\"", Regex.Replace(searchText, "([" + specialSOLRChars + "])", #"\$1"));
wildcardText = wildcardText.Replace(" ", "*");
keywordPred = keywordPred.Or(i => i.Content.MatchWildcard(wildcardText)).Or(i => i.Name.MatchWildcard(wildcardText));
}
else {
keywordPred = keywordPred.Or(i => i.Content.Contains(searchText)).Or(i => i.Name.Contains(searchText));
}
if (additionalFields != null && additionalFields.Any()) {
keywordPred = additionalFields.Aggregate(keywordPred, (current, field) => current.Or(i => i[field].Equals(searchText)));
}
//query = query.Where(i => (i.Content.Contains(searchText) || i.Name.Contains(searchText))); // more explicit call to check the content or item name for our term
query = query.Where(keywordPred);
}
if (language == string.Empty) {
language = Sitecore.Context.Language.ToString();
}
if (language != null) {
query = query.Filter(i => i.Language.Equals(language));
}
query = query.Page(currentPage, pageSize);
if (additionalWhere != null) {
query = query.Where(additionalWhere);
}
if (additionalFilter != null) {
query = query.Filter(additionalFilter);
}
query = query.ApplySecurityFilter();
FacetResults resultFacets = null;
if (facets != null && facets.Any()) {
resultFacets = facets.Aggregate(query, (current, fname) => current.FacetOn(i => i[fname])).GetFacets();
}
// calling this before applying facetFilter should allow us to get a total facet set
// instead of just those related to the current result set
// var resultFacets = query.GetFacets();
// apply after getting facets for more complete facet list
if (facetFilter != null) {
query = query.Where(facetFilter);
}
if (sortField != null)
{
if (sortDirection == SortDirection.Ascending)
{
query = query.OrderBy(x => x[sortField]);
}
else
{
query = query.OrderByDescending(x => x[sortField]);
}
}
var results = query.GetResults(); // this enumerates the actual results
return new SearchResults<T>(results.Hits, results.TotalSearchResults, resultFacets);
}
}
When I try this I get the following error message:
Server Error in '/' Application.
No constant node in query node of type: 'Sitecore.ContentSearch.Linq.Nodes.EqualNode'. Left: 'Sitecore.ContentSearch.Linq.Nodes.FieldNode'. Right: 'Sitecore.ContentSearch.Linq.Nodes.FieldNode'.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NotSupportedException: No constant node in query node of type: 'Sitecore.ContentSearch.Linq.Nodes.EqualNode'. Left: 'Sitecore.ContentSearch.Linq.Nodes.FieldNode'. Right: 'Sitecore.ContentSearch.Linq.Nodes.FieldNode'.
Source Error:
Line 548: FacetResults resultFacets = null;
Line 549: if (facets != null && facets.Any()) {
Line 550: resultFacets = facets.Aggregate(query, (current, fname) => current.FacetOn(i => i[fname])).GetFacets();
Line 551: }
Line 552: // calling this before applying facetFilter should allow us to get a total facet set
From what I can understand about the error message it seems to not like that I am trying to compare two different fields to each other instead of comparing a field to a constant. The other odd thing is that the error seems to be pointing to a line of code that has to do with aggregating facets. I did a Google search and came up with absolutely nothing relating to this error. Any ideas?
Thanks,
Corey
I think what you are trying is not possible, and if you look at this that might indeed be the case. A solution that is given there is to put your logic in the index: create a ComputedField that checks your dates and puts a value in the index that you can search on (can be a simple boolean).
You will need to split your logic though - the query on the date range can still be done in the predicate (as it is relative to the current date) but the comparison of first and last should be done on index time instead of on query time.
I have an IEnumerable and a predicate (Func) and I am writing a method that shall return a value if only one instance in the list matches the predicate. If the criteria is matched by none, then none was found. If the criteria is matched by many instances, then the predicate was insufficient to successfully identify the desired record. Both cases should return null.
What is the recommended way to express this in LINQ that does not result in multiple enumerations of the list?
The LINQ operator SingleOrDefault will throw an exception if multiple instances are found.
The LINQ operator FirstOrDefault will return the first even when multiple was found.
MyList.Where(predicate).Skip(1).Any()
...will check for ambiguity, but will not retain the desired record.
It seems that my best move is to grab the Enumerator from MyList.Where(predicate) and retain the first instance if accessing the next item fails, but it seems slightly verbose.
Am I missing something obvious?
The "slightly verbose" option seems reasonable to me, and can easily be isolated into a single extension method:
// TODO: Come up with a better name :)
public static T SingleOrDefaultOnMultiple<T>(this IEnumerable<T> source)
{
// TODO: Validate source is non-null
using (var iterator = source.GetEnumerator())
{
if (!iterator.MoveNext())
{
return default(T);
}
T first = iterator.Current;
return iterator.MoveNext() ? default(T) : first;
}
}
Update: Here is a more general approach which might be more reusable.
public static IEnumerable<TSource> TakeIfCountBetween<TSource>(this IEnumerable<TSource> source, int minCount, int maxCount, int? maxTake = null)
{
if (source == null)
throw new ArgumentNullException("source");
if (minCount <= 0 || minCount > maxCount)
throw new ArgumentException("minCount must be greater 0 and less than or equal maxCount", "minCount");
if (maxCount <= 0)
throw new ArgumentException("maxCount must be greater 0", "maxCount");
int take = maxTake ?? maxCount;
if (take > maxCount)
throw new ArgumentException("maxTake must be lower or equal maxCount", "maxTake");
if (take < minCount)
throw new ArgumentException("maxTake must be greater or equal minCount", "maxTake");
int count = 0;
ICollection objCol;
ICollection<TSource> genCol = source as ICollection<TSource>;
if (genCol != null)
{
count = genCol.Count;
}
else if ((objCol = source as ICollection) != null)
{
count = objCol.Count;
}
else
{
using (IEnumerator<TSource> enumerator = source.GetEnumerator())
{
while (enumerator.MoveNext() && ++count < maxCount);
}
}
bool valid = count >= minCount && count <= maxCount;
if (valid)
return source.Take(take);
else
return Enumerable.Empty<TSource>();
}
Usage:
var list = new List<string> { "A", "B", "C", "E", "E", "F" };
IEnumerable<string> result = list
.Where(s => s == "A")
.TakeIfCountBetween(1, 1);
Console.Write(string.Join(",", result)); // or result.First()
In my controller I have a method that receives a decimal value (id).
The objective of this method is to recover a list of old revisions from a database table containing work permits. Each record on this table has a WorkPermitID as a primary key and OldRevisionWorkPermitID referencing the ID of the previous version.
I have no problems when collecting the children IDs (old versions), but it raises an exception indicating that LINQ to Entities does not recognize .ToString() method.
What I'm doing wrong? I know that I need to do without converting to string (WorkPermitID is defined as numeric in the database), but I tried several ways with no success.
public ActionResult GetVersions(decimal id){
var model = new PermisosTrabajoModel();
List<string> ChildIDs = new List<string>();
var WP = OtWeb.WorkPermit.Single(q => q.WorkPermitID == id);
while (WP.OldRevisionWorkPermitID != null)
{
var child = WP.OldRevisionWorkPermitID;
ChildIDs.Add(child.ToString());
WP = OtWeb.WorkPermit.Single(q => q.WorkPermitID == child);
}
model.WPs = OtWeb.WorkPermit
.Where(q => q.DeptID == 1
&& ChildIDs.Contains(q.WorkPermitID.ToString())).ToList();
return View (model);
}
Solution1
If both of your fields are decimal... Don't use ToString(), and use a list of decimal
var model = new PermisosTrabajoModel();
var childIDs = new List<decimal>();
var WP = OtWeb.WorkPermit.Single(q => q.WorkPermitID == id);
while (WP.OldRevisionWorkPermitID != null)
{
childIDs.Add(WP.OldRevisionWorkPermitID);
WP = OtWeb.WorkPermit.Single(q => q.WorkPermitID == child);
}
model.WPs = OtWeb.WorkPermit
.Where(q => q.DeptID == 1
&& childIDs.Contains(q.WorkPermitID)).ToList();
Solution2
In linq2entities, you can use SqlFunctions.StringConvert instead of ToString() for a numeric value.
SqlFunctions.StringConvert(q.WorkPermitId)
instead of
q.WorkPermitID.ToString()
for example
I was trying to implement the jQgrid using MvcjQgrid and i got this exception.
System.NotSupportedException was unhandled by user code
Message=The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'.
Though OrdeyBy is used before Skip method why it is generating the exception? How can it be solved?
I encountered the exception in the controller:
public ActionResult GridDataBasic(GridSettings gridSettings)
{
var jobdescription = sm.GetJobDescription(gridSettings);
var totalJobDescription = sm.CountJobDescription(gridSettings);
var jsonData = new
{
total = totalJobDescription / gridSettings.PageSize + 1,
page = gridSettings.PageIndex,
records = totalJobDescription,
rows = (
from j in jobdescription
select new
{
id = j.JobDescriptionID,
cell = new[]
{
j.JobDescriptionID.ToString(),
j.JobTitle,
j.JobType.JobTypeName,
j.JobPriority.JobPriorityName,
j.JobType.Rate.ToString(),
j.CreationDate.ToShortDateString(),
j.JobDeadline.ToShortDateString(),
}
}).ToArray()
};
return Json(jsonData, JsonRequestBehavior.AllowGet);
}
GetJobDescription Method and CountJobDescription Method
public int CountJobDescription(GridSettings gridSettings)
{
var jobdescription = _dataContext.JobDescriptions.AsQueryable();
if (gridSettings.IsSearch)
{
jobdescription = gridSettings.Where.rules.Aggregate(jobdescription, FilterJobDescription);
}
return jobdescription.Count();
}
public IQueryable<JobDescription> GetJobDescription(GridSettings gridSettings)
{
var jobdescription = orderJobDescription(_dataContext.JobDescriptions.AsQueryable(), gridSettings.SortColumn, gridSettings.SortOrder);
if (gridSettings.IsSearch)
{
jobdescription = gridSettings.Where.rules.Aggregate(jobdescription, FilterJobDescription);
}
return jobdescription.Skip((gridSettings.PageIndex - 1) * gridSettings.PageSize).Take(gridSettings.PageSize);
}
And Finally FilterJobDescription and OrderJobDescription
private static IQueryable<JobDescription> FilterJobDescription(IQueryable<JobDescription> jobdescriptions, Rule rule)
{
if (rule.field == "JobDescriptionID")
{
int result;
if (!int.TryParse(rule.data, out result))
return jobdescriptions;
return jobdescriptions.Where(j => j.JobDescriptionID == Convert.ToInt32(rule.data));
}
// Similar Statements
return jobdescriptions;
}
private IQueryable<JobDescription> orderJobDescription(IQueryable<JobDescription> jobdescriptions, string sortColumn, string sortOrder)
{
if (sortColumn == "JobDescriptionID")
return (sortOrder == "desc") ? jobdescriptions.OrderByDescending(j => j.JobDescriptionID) : jobdescriptions.OrderBy(j => j.JobDescriptionID);
return jobdescriptions;
}
The exception means that you always need a sorted input if you apply Skip, also in the case that the user doesn't click on a column to sort by. I could imagine that no sort column is specified when you open the grid view for the first time before the user can even click on a column header. To catch this case I would suggest to define some default sorting that you want when no other sorting criterion is given, for example:
switch (sortColumn)
{
case "JobDescriptionID":
return (sortOrder == "desc")
? jobdescriptions.OrderByDescending(j => j.JobDescriptionID)
: jobdescriptions.OrderBy(j => j.JobDescriptionID);
case "JobDescriptionTitle":
return (sortOrder == "desc")
? jobdescriptions.OrderByDescending(j => j.JobDescriptionTitle)
: jobdescriptions.OrderBy(j => j.JobDescriptionTitle);
// etc.
default:
return jobdescriptions.OrderBy(j => j.JobDescriptionID);
}
Edit
About your follow-up problems according to your comment: You cannot use ToString() in a LINQ to Entities query. And the next problem would be that you cannot create a string array in a query. I would suggest to load the data from the DB with their native types and then convert afterwards to strings (and to the string array) in memory:
rows = (from j in jobdescription
select new
{
JobDescriptionID = j.JobDescriptionID,
JobTitle = j.JobTitle,
JobTypeName = j.JobType.JobTypeName,
JobPriorityName = j.JobPriority.JobPriorityName,
Rate = j.JobType.Rate,
CreationDate = j.CreationDate,
JobDeadline = j.JobDeadline
})
.AsEnumerable() // DB query runs here, the rest is in memory
.Select(a => new
{
id = a.JobDescriptionID,
cell = new[]
{
a.JobDescriptionID.ToString(),
a.JobTitle,
a.JobTypeName,
a.JobPriorityName,
a.Rate.ToString(),
a.CreationDate.ToShortDateString(),
a.JobDeadline.ToShortDateString()
}
})
.ToArray()
I had the same type of problem after sorting using some code from Adam Anderson that accepted a generic sort string in OrderBy.
After getting this excpetion, i did lots of research and found that very clever fix:
var query = SelectOrders(companyNo, sortExpression);
return Queryable.Skip(query, iStartRow).Take(iPageSize).ToList();
Hope that helps !
SP
While looking though some code of the project I'm working on, I've come across a pretty hefty method which does
the following:
public string DataField(int id, string fieldName)
{
var data = _dataRepository.Find(id);
if (data != null)
{
if (data.A == null)
{
data.A = fieldName;
_dataRepository.InsertOrUpdate(data);
return "A";
}
if (data.B == null)
{
data.B = fieldName;
_dataRepository.InsertOrUpdate(data);
return "B";
}
// keep going data.C through data.Z doing the exact same code
}
}
Obviously having 26 if statements just to determine if a property is null and then to update that property and do a database call is
probably very naive in implementation. What would be a better way of doing this unit of work?
Thankfully C# is able to inspect and assign class members dynamically, so one option would be to create a map list and iterate over that.
public string DataField(int id, string fieldName)
{
var data = _dataRepository.Find(id);
List<string> props = new List<string>();
props.Add("A");
props.Add("B");
props.Add("C");
if (data != null)
{
Type t = typeof(data).GetType();
foreach (String entry in props) {
PropertyInfo pi = t.GetProperty(entry);
if (pi.GetValue(data) == null) {
pi.SetValue(data, fieldName);
_dataRepository.InsertOrUpdate(data);
return entry;
}
}
}
}
You could just loop through all the character from 'A' to 'Z'. It gets difficult because you want to access an attribute of your 'data' object with the corresponding name, but that should (as far as I know) be possible through the C# reflection functionality.
While you get rid of the consecutive if-statements this still won't make your code nice :P
there is a fancy linq solution for your problem using reflection:
but as it was said before: your datastructure is not very well thought through
public String DataField(int id, string fieldName)
{
var data = new { Z = "test", B="asd"};
Type p = data.GetType();
var value = (from System.Reflection.PropertyInfo fi
in p.GetProperties().OrderBy((fi) => fi.Name)
where fi.Name.Length == 1 && fi.GetValue(data, null) != null
select fi.Name).FirstOrDefault();
return value;
}
ta taaaaaaaaa
like that you get the property but the update is not yet done.
var data = _dataRepository.Find(id);
If possible, you should use another DataType without those 26 properties. That new DataType should have 1 property and the Find method should return an instance of that new DataType; then, you could get rid of the 26 if in a more natural way.
To return "A", "B" ... "Z", you could use this:
return (char)65; //In this example this si an "A"
And work with some transformation from data.Value to a number between 65 and 90 (A to Z).
Since you always set the lowest alphabet field first and return, you can use an additional field in your class that tracks the first available field. For example, this can be an integer lowest_alphabet_unset and you'd update it whenever you set data.{X}:
Init:
lowest_alphabet_unset = 0;
In DataField:
lowest_alphabet_unset ++;
switch (lowest_alphabet_unset) {
case 1:
/* A is free */
/* do something */
return 'A';
[...]
case 7:
/* A through F taken */
data.G = fieldName;
_dataRepository.InsertOrUpdate(data);
return 'G';
[...]
}
N.B. -- do not use, if data is object rather that structure.
what comes to my mind is that, if A-Z are all same type, then you could theoretically access memory directly to check for non null values.
start = &data;
for (i = 0; i < 26; i++){
if ((typeof_elem) *(start + sizeof(elem)*i) != null){
*(start + sizeof(elem)*i) = fieldName;
return (char) (65 + i);
}
}
not tested but to give an idea ;)