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ObjectQuery(Of T).Where Method

Limits the query to results that match specified filtering criteria.

Namespace:  System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

'Declaration
Public Function Where ( _
	predicate As String, _
	ParamArray parameters As ObjectParameter() _
) As ObjectQuery(Of T)

Parameters

predicate
Type: System.String

The filter predicate.

parameters
Type: System.Data.Objects.ObjectParameter()

Zero or more parameters that are used in this method.

Return Value

Type: System.Data.Objects.ObjectQuery(Of T)
A new ObjectQuery(Of T) instance that is equivalent to the original instance with WHERE applied.

ExceptionCondition
ArgumentNullException

predicate is Nothing.

-or-

parameters is Nothing.

ArgumentException

The predicate is an empty string.

This example is based on the Adventure Works Sales Model. The example creates a new ObjectQuery(Of T) that contains results of the existing query filtered by the following criteria: "it.ProductID = 900".

Dim productID = 900
Using context As New AdventureWorksEntities()
    Dim queryString As String = "SELECT VALUE product FROM AdventureWorksEntities.Products AS product" 

    Dim productQuery1 As New ObjectQuery(Of Product)(queryString, context, MergeOption.NoTracking)

    Dim productQuery2 As ObjectQuery(Of Product) = productQuery1.Where("it.ProductID = @productID")
    productQuery2.Parameters.Add(New ObjectParameter("productID", productID))

    ' Iterate through the collection of Product items.  
    For Each result As Product In productQuery2
        Console.WriteLine("Product Name: {0}; Product ID: {1}", result.Name, result.ProductID)
    Next 
End Using

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4
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