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SqlDataSource.Select Method

System.Web.UI.WebControls Namespace   SqlDataSource Class


.NET Framework version 2.0

Retrieves data from the underlying database using the SelectCommand SQL string and any parameters that are in the SelectParameters collection.

[ VB ]
Public Sub Select ( _
   ByVal arguments As DataSourceSelectArguments _
) As IEnumerable

[ C# ]
public IEnumerable Select (
   DataSourceSelectArguments arguments
);

[ C++ ]
public: IEnumerable Select (
   DataSourceSelectArguments* arguments
);

[ JScript ]
public function Select (
   arguments : DataSourceSelectArguments
) : IEnumerable;

Parameters

arguments
A DataSourceSelectArguments used to request operations on the data beyond basic data retrieval.

Return Value

An IEnumerable list of data rows.

Exceptions


Exception Type Condition
InvalidOperationException The SqlDataSource cannot establish a connection with the underlying data source.

Remarks

The Select method returns a DataView object, if the DataSourceMode property is set to the DataSet value, or a IDataReader object, if the DataSourceMode property is set to the DataReader value.

Before the Select operation is performed, the OnSelecting method is called to raise the Selecting event. You can handle this event to examine the values of the parameters and to perform any preprocessing before the Select operation.

After the Select operation completes, the OnSelected method is called to raise the Selected event. You can handle this event to examine any return values and error codes and to perform any post-processing.

If the DataSourceMode property is set to the DataSet value and caching is enabled, the SqlDataSource object retrieves data from and saves data to the cache during the Select operation. The cache is created, discarded, or refreshed based on the caching behavior that is specified by the combination of the CacheDuration and CacheExpirationPolicy properties.

SECURITY NOTE: When you are using client impersonation under Microsoft Windows authentication, the data is cached when the first user accesses the data. If another user requests the same data, the data is retrieved from the cache. The data is not retrieved by making another call to the database to verify the user's access to the data. If you expect more than one user to access the data, and you want each retrieval to the data to be verified by the security configurations for the database, do not use caching.

If the DataSourceMode is set to the DataSet value and a FilterExpression property has been specified, it is evaluated with any supplied FilterParameters properties and the resulting filter is applied to the list of data during the Select operation.

The Select method delegates to the Select method of the SqlDataSourceView object that is associated with the SqlDataSource control. To perform a data retrieval operation, the SqlDataSourceView builds a DbCommand object using the SelectCommand text and any associated SelectParameters, and then executes the DbCommand against the underlying database.

See Also

SqlDataSource Members   Delete   Insert   Update Skip Navigation Links




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