System.Web.UI.WebControls Namespace   SqlDataSource Class

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.NET Framework version 2.0

Sets or retrieves the SQL string that the SqlDataSource control uses to retrieve data from the underlying database.

Inline	<asp:SqlDataSource selectcommand = strSQL ... >
Script	SqlDataSource.SelectCommand [ = strSQL ]

strSQL

An SQL string that the SqlDataSource uses to retrieve data.

The property is read/write with no default value.

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 on 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.

NOTE: For security purposes, the SelectCommand property is not stored in 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.

The following code examples demonstrate how to set the SelectCommand property of an AccessDataSource control.

Basically, retrieving data from a Microsoft Access database using the AccessDataSource control can be done in two ways:

1. by specifying the SQL query to execute directly against the data file, or
2. by referencing a query stored in the data file itself.

In the first case, you specify the SQL query by setting the AccessDataSource control's SelectCommand property as shown in the following example.

<asp:accessdatasource id="ProductType" runat="server"
   datafile="~/app_data/gear.mdb"
   selectcommand="SELECT distinct Type FROM Products"
   datasourcemode="DataReader" />

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In the second case, you specify the name of the Microsoft Access query to execute as the value of the SelectCommand, and set the SelectCommandType property value to StoredProcedure, as shown in the following example.

<asp:accessdatasource id="zipcodes" runat="server"
   datafile="~/app_data/usa.mdb"
   selectcommand="[Zipcodes By State and County]"
   selectcommandtype="StoredProcedure">

   <selectparameters>
      <asp:controlparameter controlid="lstStates" 
         propertyname="SelectedValue" />
      <asp:controlparameter controlid="lstCounties" 
         propertyname="SelectedValue" />
   </selectparameters>

</asp:accessdatasource>

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SelectCommandType

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