I want to filter list as below. I have a class & I want to filter values from that are in my filter string. I have achieved my result by a for loop but need a way without for loop.
Public Class WorkStationDetails<br><br>
Property CountryId As Integer<br>
Property CountryName As String<br>
Property TotalWrkStn As Integer<br>
Property ExistingWrkStn As Integer<br>
Property RemainingWrkStn As Integer<br><br>
End Class
Dim WrkStnDtl As List(Of WorkStationDetails)
Dim FilterWrkStnDtl As List(Of WorkStationDetails)
Dim Numbers As String()
Numbers = "1,5,6,2,9".Split(",")
For i As Integer = 0 To Numbers.Length - 1
FilterWrkStnDtl.AddRange(WrkStnDtl.FindAll(Function(p) (p.CountryId = Numbers(i))))
Next
Note: I want to achieve it like subquery in sql server.
I think you want something like this"
var numbers = "1,5,6,2,9".Split(',');
var selected = WrkStnDtl.Where(w => numbers.Contains(w.CountryId)).ToList();
Related
How to select record based on multiple values search in one column using linq query.
like product id is "product1", "product2","product3" n number of values we have
You can use the .Contains method to check whether a value is within a list.
var values = new List<string>() { "Prod1", "Prod2", "Prod3" };
var query = context.Set<Product>().Where(x => values.Contains(x.Name));
You could use something like (this is VB.Net, change to C# if necessary)
Dim result = products.Where(Function(p) p.ID = "product1" Or p.ID = "product2" Or p.ID = "product3", ...)
Alternatively, you could pull it all back to the client and use .Contains, like so:
Dim materializedProducts = products.ToList()
Dim result = materializedProducts.Where(Function(p) {"product1", "product2", "{product3}", ...}.Contains(p.ID))
Going further still, you could create an extension method (generic, if that floats your boat) called IsIn or similar that allows you to swap the order of the collection and the search value:
<Extension()>
Public Function IsIn(Of T)(ByVal searchValue As T,
ByVal searchSet As IEnumerable(Of T))
Return searchset.Contains(searchValue)
End Sub
Dim materializedProducts = products.ToList()
Dim result = materializedProducts.Where(Function(p) p.ID.IsIn({"product1", "product2", "{product3}", ...}))
I have datatable which it first row is headers
I need specific column for this datatable according to the header
I know how to get the column if know its index.
The problem is how to get the index
Dim columnIndex as integer
Dim headerRow As DataRow = dt.Rows(0)
Dim colHeader As string ="abc"
columnIndex=???
Dim result = dt.Rows.Cast(Of DataRow)().[Select](Function(row) row(columnIndex)).Distinct().ToList()
Thanks
You may use the dt.Rows.IndexOf
Dim ValueToSearch AS string = ...
columnIndex = dt.AsEnumerable().Where(Function(x) x.Field(of String)(colHeader) = ValueToSearch).Select(Function(x) dt.Rows.IndexOf(x)).SingleOrDefault()
The above will work if the where clause returns only one or zero rows. If this is not true then you may dismiss the SingleOrDefault and then loop through the results, ie:
columnIndex = dt.AsEnumerable().Where(Function(x) x.Field(of String)(colHeader) = ValueToSearch).Select(Function(x) dt.Rows.IndexOf(x))
For Each i in columnIndex
Console.WriteLine("Value found in row with index " + i.ToString())
Next
Giannis
I am getting the correct Employee Id in the VarEmpID variable. When I click on delete
It is giving me
Unable to cast object of type 'System.Data.Linq.DataQuery`1[my name space]' to type 'namespace'.
enter code here
Protected Sub radGrid1_DeleteCommand(ByVal source As Object, ByVal e As GridCommandEventArgs) Handles radGrid1.DeleteCommand
Dim VarEmpId As String = (CType(e.Item, GridDataItem)).OwnerTableView.DataKeyValues(e.Item.ItemIndex)("EmpId").ToString()
Using dc1 As New EmployeesDataClassesDataContext()
Dim EmployeeEntry = (From p In dc1.Employees
Where (p.EmpId = VarEmpId)
Select p)
dc1.Employees.DeleteOnSubmit(EmployeeEntry)
dc1.SubmitChanges()
Dim queryResults = (From queryItem In EmployeeEntry Select queryItem).ToList()
If queryResults.Any Then
radGrid1.DataSource = queryResults
radGrid1.DataBind()
End If
End Using
End Sub
dc1.Employees.DeleteOnSubmit(EmployeeEntry)
That method expects an Employee instance. Instead, you passed in an employee query.
Dim EmployeeEntry = ( query )
This is a query, not an entry. Consider calling Enumerable.First to get the first result of the query, and then deleting that.
Modified added Dim EmployeeEntry = (From p In dc1.Employees Where (p.EmpId = VarEmpId) Select p).singleorDefault() After that commented out the queryresults part and binded data again it solved my problem. – SmilingLily
I have been trying to access the data returned from a dynamic linq query as an anonymous type. The advice I have found suggests that I should create a custom type and use it in the Select clause with the new keyword. I was directed to the followed Question for a code example:
System.LINQ.Dynamic: Select(" new (...)") into a List<T> (or any other enumerable collection of <T>)
This was indeed an excellent example which I incorporated into my code (which is VB so I had to do some translation).
My code compiles fine but When I run it , I get the error following error:
"Value cannot be null. Parameter name: member" at the following line from the example:
bindings[i] = Expression.Bind(type.GetProperty(properties[i].Name), expressions[i]);
This seems to be linked to expressions(i), which correctly contains two items as I am returning two fields from the database table. properties(i) holds the name of those two fields correctly. Any ideas as to what the value for member is supposed to be and where it should be found? Is it something from the database?
The where clause of this query works and when I run it as an anonymous type it brings back records (or rather two fields from records). The returned fields contain data not nulls.
Here is my VB version of the code from the example provided in the earlier Question. I have bolded or ** the line where the error occurs. Any ideas as to what is causing this?
Much appreciated.
Function ParseNew() As Expression
NextToken()
ValidateToken(TokenId.OpenParen, Res.OpenParenExpected)
NextToken()
Dim properties As New List(Of DynamicProperty)()
Dim expressions As New List(Of Expression)()
Do
Dim exprPos = tokenVal.pos
Dim expr = ParseExpression()
Dim propName As String
If TokenIdentifierIs("as") Then
NextToken()
propName = GetIdentifier()
NextToken()
Else
Dim [me] As MemberExpression = TryCast(expr, MemberExpression)
If [me] Is Nothing Then Throw ParseError(exprPos, Res.MissingAsClause)
propName = [me].Member.Name
End If
expressions.Add(expr)
properties.Add(New DynamicProperty(propName, expr.Type))
If tokenVal.id <> TokenId.Comma Then Exit Do
NextToken()
Loop
ValidateToken(TokenId.CloseParen, Res.CloseParenOrCommaExpected)
NextToken()
'CODE added to support strongly-typed returns
Dim type As Type = If(newResultType, DynamicExpression.CreateClass(properties))
Dim bindings(properties.Count - 1) As MemberBinding
For i As Integer = 0 To bindings.Length - 1
**bindings(i) = Expression.Bind(type.GetProperty(properties(i).Name), expressions(i))**
Next
Return Expression.MemberInit(Expression.[New](type), bindings)
End Function
I want to get a collection of Product entities where the product.Description property contains any of the words in a string array.
It would look something like this (result would be any product which had the word "mustard OR "pickles" OR "relish" in the Description text):
Dim products As List(Of ProductEntity) = New ProductRepository().AllProducts
Dim search As String() = {"mustard", "pickles", "relish"}
Dim result = From p In products _
Where p.Description.Contains(search) _
Select p
Return result.ToList
I already looked at this similar question but couldn't get it to work.
Since you want to see if search contains a word which is contained in the description of p you basically need to test for each value in search if it is contained in the description of p
result = from p in products
where search.Any(val => p.Description.Contains(val))
select p;
This is c# syntax for the lambda method since my vb is not that great
Dim result = From p in products _
Where search.Any(Function(s) p.Description.Contains(s))
Select p
You can use a simple LINQ query, if all you need is to check for substrings:
var q = words.Any(w => myText.Contains(w));
// returns true if myText == "This password1 is weak";
If you want to check for whole words, you can use a regular expression:
Matching against a regular expression that is the disjunction of all the words:
// you may need to call ToArray if you're not on .NET 4
var escapedWords = words.Select(w => #"\b" + Regex.Escape(w) + #"\b");
// the following line builds a regex similar to: (word1)|(word2)|(word3)
var pattern = new Regex("(" + string.Join(")|(", escapedWords) + ")");
var q = pattern.IsMatch(myText);
Splitting the string into words with a regular expression, and testing for membership on the words collection (this will get faster if you use make words into a HashSet instead of a List):
var pattern = new Regex(#"\W");
var q = pattern.Split(myText).Any(w => words.Contains(w));
In order to filter a collection of sentences according to this criterion all you have to do its put it into a function and call Where:
// Given:
// bool HasThoseWords(string sentence) { blah }
var q = sentences.Where(HasThoseWords);
Or put it in a lambda:
var q = sentences.Where(s => Regex.Split(myText, #"\W").Any(w => words.Contains(w)));
Ans From => How to check if any word in my List<string> contains in text by #R. Martinho Fernandes