This documentation is archived and is not being maintained.

ObjectQuery<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)

public ObjectQuery<T> Where(
	string predicate,
	params ObjectParameter[] parameters
)

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<T>
A new ObjectQuery<T> instance that is equivalent to the original instance with WHERE applied.

ExceptionCondition
ArgumentNullException

predicate is null.

-or-

parameters is null.

ArgumentException

The predicate is an empty string.

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


int productID = 900;
using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    string queryString =
        @"SELECT VALUE product FROM 
            AdventureWorksEntities.Products AS product";

    ObjectQuery<Product> productQuery1 =
        new ObjectQuery<Product>(queryString,
            context, MergeOption.NoTracking);

    ObjectQuery<Product> productQuery2 =
        productQuery1.Where("it.ProductID = @productID");

    productQuery2.Parameters.Add(new ObjectParameter("productID", productID));

    // Iterate through the collection of Product items.
    foreach (Product result in productQuery2)
    {
        Console.WriteLine("Product Name: {0}; Product ID: {1}",
            result.Name, result.ProductID);
    }
}


.NET Framework

Supported in: 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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