ASPxComboBox.ItemsRequestedByFilterCondition Event

Enables you to implement custom selection of the requested items by the filter conditions.

Assembly : DevExpress.Web.v25.2.dll

Declaration

C#
VB.NET

csharp

public event ListEditItemsRequestedByFilterConditionEventHandler ItemsRequestedByFilterCondition

Public Event ItemsRequestedByFilterCondition As ListEditItemsRequestedByFilterConditionEventHandler

Event Data

The ItemsRequestedByFilterCondition event's data class is ListEditItemsRequestedByFilterConditionEventArgs. The following properties provide information specific to this event:

Property	Description
BeginIndex	Gets an integer value that identifies the begin index of the editor’s items.
EndIndex	Gets an integer value that identifies the end index of the editor’s items.
Filter	Gets a string that represents a filter condition for the editor’s items.

Remarks

This event is a wrapper of the ComboBoxProperties.ItemsRequestedByFilterCondition event.

Online Example

View Example: Grid View for ASP.NET Bootstrap - How to initialize a combo box column in batch edit mode

Example

The following section of the Filtering Large Data Source online demo illustrates how the ASPxComboBox.ItemsRequestedByFilterCondition and ASPxComboBox.ItemRequestedByValue events of the ASPxComboBox editor can be handled to filter the editor’s data source containing a large number of records.

Note

To work properly, both the ItemsRequestedByFilterCondition and ItemRequestedByValue events should be handled.

C#
ASPX

csharp

protected void ASPxComboBox_OnItemsRequestedByFilterCondition_SQL(object source, 
ListEditItemsRequestedByFilterConditionEventArgs e) {
         ASPxComboBox comboBox = (ASPxComboBox)source;
         SqlDataSource1.SelectCommand = @"SELECT OID, [From], Sent, Subject 
             FROM (select OID, [From], Sent, Subject, row_number() over(order by t.Sent) as [rn] 
             from dbo.ServerSideGridTest as t WHERE ((t.Subject LIKE @filter) OR (t.[From] 
              LIKE @filter))) as st where st.[rn] between @startIndex and @endIndex";
         SqlDataSource1.SelectParameters.Clear();
         SqlDataSource1.SelectParameters.Add("filter", TypeCode.String, string.Format("%{0}%", e.Filter));
         SqlDataSource1.SelectParameters.Add("startIndex", TypeCode.Int64, (e.BeginIndex + 1).ToString());
         SqlDataSource1.SelectParameters.Add("endIndex", TypeCode.Int64, (e.EndIndex + 1).ToString());
         comboBox.DataSource = SqlDataSource1;
         comboBox.DataBind();
}

protected void ASPxComboBox_OnItemRequestedByValue_SQL(object source, 
ListEditItemRequestedByValueEventArgs e) {
    ASPxComboBox comboBox = (ASPxComboBox)source;
    SqlDataSource1.SelectCommand = @"SELECT OID, Subject, [From], Sent 
        FROM dbo.ServerSideGridTest WHERE (OID = @OID) ORDER BY Sent";
    SqlDataSource1.SelectParameters.Add("OID", TypeCode.Int64, e.Value.ToString());
    ...
    comboBox.DataSource = SqlDataSource1;
    comboBox.DataBind();
}

aspx

<dxe:ASPxComboBox ID="ASPxComboBox1" runat="server" 
EnableCallbackMode="true" CallbackPageSize="10" 
    IncrementalFilteringMode="Contains" ValueType="System.String" ValueField="OID" 
    OnItemsRequestedByFilterCondition="ASPxComboBox_OnItemsRequestedByFilterCondition_SQL" 
    OnItemRequestedByValue="ASPxComboBox_OnItemRequestedByValue_SQL"  
    TextFormatString="{0};{1}" TextField="From" Width="100%" DropDownWidth="610">
    <Columns>
        <dxe:ListBoxColumn FieldName="Subject" Width="300px"/>
        <dxe:ListBoxColumn FieldName="From" Width="80px"/>
        <dxe:ListBoxColumn FieldName="Sent"/>
    </Columns>
</dxe:ASPxComboBox>