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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 anempty 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".

using (AdventureWorksEntities advWorksContext =
    new AdventureWorksEntities())
{
    try
    {
        string queryString =
            @"SELECT VALUE Product FROM 
                AdventureWorksEntities.Product AS Product";

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

        ObjectQuery<Product> productQuery2 = 
            productQuery1.Where("it.ProductID = 900");

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

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

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

.NET Framework

Supported in: 3.5 SP1
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