SqlDataSource.SelectCommand Property
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Gets or sets the SQL string that the SqlDataSource control uses to retrieve data from the underlying database.
public:
property System::String ^ SelectCommand { System::String ^ get(); void set(System::String ^ value); };public string SelectCommand { get; set; }member this.SelectCommand : string with get, setPublic Property SelectCommand As StringProperty Value
An SQL string or the name of a stored procedure that the SqlDataSource uses to retrieve data.
Examples
This section contains two code examples. The first code example demonstrates how to set the SelectCommand text to a basic SQL query to retrieve data from an ODBC-compliant database and display it in a GridView control. The second code example demonstrates how to set the SelectCommand text to the name of a stored procedure and the SelectCommandType property to the StoredProcedure value to retrieve data from a Microsoft SQL Server database and display it in a DropDownList control.
In both examples, there is no need to explicitly call the Select method because the data-bound controls that are attached to the data source control through the DataSourceID property will automatically call the Select method during the PreRender phase.
The following code example demonstrates how to set the SelectCommand text to a basic SQL query to retrieve data from an ODBC-compliant database and display it in a GridView control.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<!-- This example uses a Northwind database that is hosted by an ODBC-compliant
database. To run this sample, create an ODBC DSN to any database that hosts
the Northwind database, including Microsoft SQL Server or Microsoft Access,
change the name of the DSN in the ConnectionString, and view the page.
-->
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ProviderName="System.Data.Odbc"
DataSourceMode="DataSet"
ConnectionString="dsn=myodbc3dsn;"
SelectCommand="SELECT FirstName, LastName, Title FROM Employees">
</asp:SqlDataSource>
<asp:GridView
id="GridView1"
runat="server"
AllowSorting="True"
DataSourceID="SqlDataSource1">
</asp:GridView>
</form>
</body>
</html>
<%@Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<!-- This example uses a Northwind database that is hosted by an ODBC-compliant
database. To run this sample, create an ODBC DSN to any database that hosts
the Northwind database, including Microsoft SQL Server or Microsoft Access,
change the name of the DSN in the ConnectionString, and view the page.
-->
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ProviderName="System.Data.Odbc"
DataSourceMode="DataSet"
ConnectionString="dsn=myodbc3dsn;"
SelectCommand="SELECT FirstName, LastName, Title FROM Employees">
</asp:SqlDataSource>
<asp:GridView
id="GridView1"
runat="server"
AllowSorting="True"
DataSourceID="SqlDataSource1">
</asp:GridView>
</form>
</body>
</html>
The following code example demonstrates how to set the SelectCommand text to the name of a stored procedure and the SelectCommandType property to the StoredProcedure value to retrieve data from a SQL Server database and display it in a DropDownList control. The SelectCommand property can be an SQL query or the name of a stored procedure, if the data source supports stored procedures.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:DropDownList
id="DropDownList1"
runat="server"
DataTextField="LastName"
DataSourceID="SqlDataSource1" />
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommandType="StoredProcedure"
SelectCommand="sp_lastnames">
</asp:SqlDataSource>
<!--
The sp_lastnames stored procedure is
CREATE PROCEDURE sp_lastnames AS
SELECT LastName FROM Employees
GO
-->
</form>
</body>
</html>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:DropDownList
id="DropDownList1"
runat="server"
DataTextField="LastName"
DataSourceID="SqlDataSource1" />
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
SelectCommandType = "StoredProcedure"
SelectCommand="sp_lastnames">
</asp:SqlDataSource>
<!--
The sp_lastnames stored procedure is
CREATE PROCEDURE sp_lastnames AS
SELECT LastName FROM Employees
GO
-->
</form>
</body>
</html>
Remarks
The SelectCommand property represents an SQL query or the name of a stored procedure, and is used by the Select method to retrieve data from a SQL Server database. If you use an asterisk (*) in the Select command to select all columns, and if you use automatic code generation to perform update or delete operations, make sure that no columns have spaces in their names.
Because different database products use different varieties of SQL, the syntax of the SQL string depends on the current ADO.NET provider being used, which is identified by the ProviderName property. If the SQL string is a parameterized query or command, the placeholder of the parameter also depends on the ADO.NET provider being used. For example, if the provider is the System.Data.SqlClient, which is the default provider for the SqlDataSource class, the placeholder of the parameter is '@parameterName'. However, if the provider is set to the System.Data.Odbc or System.Data.OleDb, the placeholder of the parameter is '?'. For more information about parameterized SQL queries and commands, see Using Parameters with the SqlDataSource Control.
The SelectCommand property can be an SQL string or the name of a stored procedure, if the data source supports stored procedures.
The SelectCommand property delegates to the SelectCommand property of the SqlDataSourceView object that is associated with the SqlDataSource control.
Important
For security purposes, the SelectCommand property is not stored is view state. Because it is possible to decode the contents of view state on the client, storing sensitive information about the database structure in view state could result in an information disclosure vulnerability.
Important
Values are inserted into parameters without validation, which is a potential security threat. Use the Filtering event to validate parameter values before executing the query. For more information, see Script Exploits Overview.
