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How to: Execute a Parameterized Entity SQL Query Using EntityCommand

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This topic shows how to execute an Entity SQL query that has parameters by using an EntityCommand object.

To run the code in this example

  1. Add the AdventureWorks Sales Model to your project and configure your project to use the Entity Framework. For more information, see How to: Use the Entity Data Model Wizard.

  2. In the code page for your application, add the following using directives (Imports in Visual Basic):

    using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Data.EntityClient;
using System.Data.Metadata.Edm;

    Imports System.Collections.Generic
Imports System.Collections
Imports System.Data.Common
Imports System.Data
Imports System.IO
Imports System.Data.SqlClient
Imports System.Data.EntityClient
Imports System.Data.Metadata.Edm

Example

The following example shows how to construct a query string with two parameters. It then creates an EntityCommand, adds two parameters to the EntityParameter collection of that EntityCommand, and iterates through the collection of Contact items.

using (EntityConnection conn =
    new EntityConnection("name=AdventureWorksEntities"))
{
    conn.Open();
    // Create a query that takes two parameters.
    string esqlQuery =
        @"SELECT VALUE Contact FROM AdventureWorksEntities.Contacts
                    AS Contact WHERE Contact.LastName = @ln AND
                    Contact.FirstName = @fn";

    using (EntityCommand cmd = new EntityCommand(esqlQuery, conn))
    {
        // Create two parameters and add them to
        // the EntityCommand's Parameters collection
        EntityParameter param1 = new EntityParameter();
        param1.ParameterName = "ln";
        param1.Value = "Adams";
        EntityParameter param2 = new EntityParameter();
        param2.ParameterName = "fn";
        param2.Value = "Frances";

        cmd.Parameters.Add(param1);
        cmd.Parameters.Add(param2);

        using (DbDataReader rdr = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
        {
            // Iterate through the collection of Contact items.
            while (rdr.Read())
            {
                Console.WriteLine(rdr["FirstName"]);
                Console.WriteLine(rdr["LastName"]);
            }
        }
    }
    conn.Close();
}

Using conn As New EntityConnection("name=AdventureWorksEntities")
    conn.Open()
    ' Create a query that takes two parameters. 
    Dim esqlQuery As String = "SELECT VALUE Contact FROM AdventureWorksEntities.Contacts " & _
        " AS Contact WHERE Contact.LastName = @ln AND Contact.FirstName = @fn"

    Using cmd As New EntityCommand(esqlQuery, conn)
        ' Create two parameters and add them to 
        ' the EntityCommand's Parameters collection 
        Dim param1 As New EntityParameter()
        param1.ParameterName = "ln"
        param1.Value = "Adams"
        Dim param2 As New EntityParameter()
        param2.ParameterName = "fn"
        param2.Value = "Frances"

        cmd.Parameters.Add(param1)
        cmd.Parameters.Add(param2)

        Using rdr As DbDataReader = cmd.ExecuteReader(CommandBehavior.SequentialAccess)
            ' Iterate through the collection of Contact items. 
            While rdr.Read()
                Console.WriteLine(rdr("FirstName"))
                Console.WriteLine(rdr("LastName"))
            End While
        End Using
    End Using
    conn.Close()
End Using

See also