ObjectQuery<T>.Where Method (String, ObjectParameter[])


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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


Type: System.String

The filter predicate.

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.

Exception Condition

predicate is null.


parameters is null.


The predicate is an empty string.

This example is based on the AdventureWorks 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
Available since 3.5
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