SqlDataSource.FilterExpression Property (System.Web.UI.WebControls)

FilterExpression Property

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Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

SqlDataSource..::.FilterExpression Property

Gets or sets a filtering expression that is applied when the Select method is called.

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in System.Web.dll)

Syntax

Visual Basic (Declaration)

Public Property FilterExpression As String

Visual Basic (Usage)

Dim instance As SqlDataSource
Dim value As String

value = instance.FilterExpression

instance.FilterExpression = value

public string FilterExpression { get; set; }

Visual C++

public:
property String^ FilterExpression {
    String^ get ();
    void set (String^ value);
}

JScript

public function get FilterExpression () : String
public function set FilterExpression (value : String)

ASP.NET

<asp:SqlDataSource FilterExpression="String" />

Property Value

Type: System..::.String
A string that represents a filtering expression applied when data is retrieved using the Select method.

Exceptions

Exception	Condition
NotSupportedException	The FilterExpression property was set and the SqlDataSource is in DataReader mode.

Remarks

The syntax that is used for the FilterExpression property is a format string–style expression. The filter expression syntax is the same syntax that is accepted by the RowFilter property, because the filter expression is applied to the RowFilter property of the DataView object that is returned from executing the Select method. For more information, see Expression.

If you add parameters to the FilterParameters collection, you can also include format string placeholders (for example, "{0}") in the expression to substitute for parameter values. The placeholders are replaced according to the index of the parameter in the FilterParameters collection.

You can include parameters in the FilterExpression property. If the parameter is a string or character type, enclose the parameter in single quotation marks. Quotation marks are not required, if the parameter is a numeric type.The FilterParameters collection contains the parameters that are evaluated for the placeholders that are found in the FilterExpression property.

The SqlDataSource control supports filtering data only when in the DataSet mode.

The FilterExpression property delegates to the FilterExpression property of the SqlDataSourceView object that is associated with the SqlDataSource control.

Examples

The following code example demonstrates how to retrieve data from the Northwind database and filter it using a FilterExpression string and the FilterParameters collection. The FilterExpression property is applied any time the Select method is executed to retrieve data. In this example, the FilterExpression contains a placeholder for a filter parameter, which is contained in the FilterParameters collection. In addition, the filter parameter is a ControlParameter object that is bound to the SelectedValue property of the DropDownList control. Because the DropDownList control has its AutoPostBack property set to true, any change in the selection for the DropDownList control causes the page to post information back to the server and the GridView control to rebind to the data source control with the new filter.

Visual Basic

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html  >
    <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
        <form id="form1" runat="server">

            <p>Show all employees with the following title:
            <asp:DropDownList
                id="DropDownList1"
                runat="server"
                AutoPostBack="True">
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
            </asp:DropDownList></p>

            <asp:SqlDataSource
                id="SqlDataSource1"
                runat="server"
                ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
                SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
                FilterExpression="Title='{0}'">
                <FilterParameters>
                    <asp:ControlParameter Name="Title" ControlId="DropDownList1" PropertyName="SelectedValue"/>
                </FilterParameters>
            </asp:SqlDataSource>

            <p><asp:GridView
                id="GridView1"
                runat="server"
                DataSourceID="SqlDataSource1"
                AutoGenerateColumns="False">
                <columns>
                    <asp:BoundField Visible="False" DataField="EmployeeID" />
                    <asp:BoundField HeaderText="First Name" DataField="FirstName" />
                    <asp:BoundField HeaderText="Last Name" DataField="LastName" />
                </columns>
            </asp:GridView></p>

        </form>
    </body>
</html>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html  >
    <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
        <form id="form1" runat="server">

            <p>Show all employees with the following title:
            <asp:DropDownList
                id="DropDownList1"
                runat="server"
                AutoPostBack="True">
                <asp:ListItem Selected="True">Sales Representative</asp:ListItem>
                <asp:ListItem>Sales Manager</asp:ListItem>
                <asp:ListItem>Vice President, Sales</asp:ListItem>
            </asp:DropDownList></p>

            <asp:SqlDataSource
                id="SqlDataSource1"
                runat="server"
                ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
                SelectCommand="SELECT EmployeeID,FirstName,LastName,Title FROM Employees"
                FilterExpression="Title='{0}'">
                <FilterParameters>
                    <asp:ControlParameter Name="Title" ControlId="DropDownList1" PropertyName="SelectedValue"/>
                </FilterParameters>
            </asp:SqlDataSource>

            <p><asp:GridView
                id="GridView1"
                runat="server"
                DataSourceID="SqlDataSource1"
                AutoGenerateColumns="False">
                <columns>
                    <asp:BoundField Visible="False" DataField="EmployeeID" />
                    <asp:BoundField HeaderText="First Name" DataField="FirstName" />
                    <asp:BoundField HeaderText="Last Name" DataField="LastName" />
                </columns>
            </asp:GridView></p>

        </form>
    </body>
</html>

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0

Reference

SqlDataSource Class

SqlDataSource Members

System.Web.UI.WebControls Namespace

FilterParameters

DataSourceMode

Other Resources

ASP.NET Data Access Overview

Data Source Web Server Controls

SqlDataSource Web Server Control Overview