Implementing Type Ahead Filtering in RadGrid for ASP.NET AJAX

Environment

Product	RadGrid for ASP.NET AJAX
Version	All

Description

RadGrid for ASP.NET AJAX does not natively support "type ahead" filtering functionality similar to the RadComboBox component with the Filter="Contains" property. However, you can achieve this behavior by implementing custom JavaScript and server-side code to handle key events and dynamically filter the grid data based on user input.

This knowledge base article also answers the following questions:

• How to enable dynamic filtering without pressing Enter in RadGrid for ASP.NET AJAX?
• Is it possible to implement type-ahead filtering in RadGrid column filters?
• How can I create custom filtering behavior in RadGrid for ASP.NET AJAX?

Solution

To implement type-ahead filtering in RadGrid for ASP.NET AJAX, follow these steps:

Define the columns in the RadGrid with filtering enabled and set the FilterDelay property to control the delay before filtering occurs.

ASP.NET

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
    <AjaxSettings>
        <telerik:AjaxSetting AjaxControlID="GriSystem">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="GriSystem" />
                <telerik:AjaxUpdatedControl ControlID="HiddenField1" />
            </UpdatedControls>
        </telerik:AjaxSetting>
    </AjaxSettings>
</telerik:RadAjaxManager>

<telerik:RadGrid ID="GriSystem" runat="server" AllowFilteringByColumn="true" AllowPaging="True" Width="800px"
    AutoGenerateColumns="False" CellSpacing="0" GridLines="None" OnNeedDataSource="GriSystem_NeedDataSource"
    GroupingSettings-CaseSensitive="False" OnItemCommand="GriSystem_ItemCommand"
    OnItemCreated="GriSystem_ItemCreated">
    <GroupingSettings CaseSensitive="False" />
    <MasterTableView DataKeyNames="OrderID">
        <Columns>
            <telerik:GridBoundColumn DataField="OrderID" DataType="System.Int32"
                FilterControlAltText="Filter OrderID column" HeaderText="OrderID"
                ReadOnly="True" SortExpression="OrderID" UniqueName="OrderID">
            </telerik:GridBoundColumn>
            <telerik:GridDateTimeColumn DataField="OrderDate" DataType="System.DateTime"
                FilterControlAltText="Filter OrderDate column" HeaderText="OrderDate"
                SortExpression="OrderDate" UniqueName="OrderDate">
            </telerik:GridDateTimeColumn>
            <telerik:GridNumericColumn DataField="Freight" DataType="System.Decimal"
                FilterControlAltText="Filter Freight column" HeaderText="Freight"
                SortExpression="Freight" UniqueName="Freight">
            </telerik:GridNumericColumn>
            <telerik:GridBoundColumn DataField="ShipName"
                FilterControlAltText="Filter ShipName column" HeaderText="ShipName"
                SortExpression="ShipName" UniqueName="ShipName" FilterDelay="200"
                CurrentFilterFunction="Contains" ShowFilterIcon="false">
            </telerik:GridBoundColumn>
            <telerik:GridBoundColumn DataField="ShipCountry"
                FilterControlAltText="Filter ShipCountry column" HeaderText="ShipCountry"
                SortExpression="ShipCountry" UniqueName="ShipCountry" FilterDelay="200"
                CurrentFilterFunction="Contains" ShowFilterIcon="false">
            </telerik:GridBoundColumn>
        </Columns>
    </MasterTableView>
</telerik:RadGrid>

<asp:SqlDataSource ID="SqlDataSource1" runat="server"
    ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
    SelectCommand="SELECT [OrderID], [OrderDate], [Freight], [ShipName], [ShipCountry] FROM [Orders]"></asp:SqlDataSource>
<asp:HiddenField ID="HiddenField1" runat="server" Value="" />
<asp:Button ID="Button1" runat="server" Text="Button" OnClientClick="return false;" />

Implement JavaScript to dynamically apply filtering on keypress or paste events.

JavaScript

function pageLoad() {
    let hiddenField = $get('<%= HiddenField1.ClientID %>');

    if (hiddenField.value !== "") {
        let textBox = $get(hiddenField.value);
        let text = textBox.value;

        textBox.onfocus = function () {
            this.value = "";
            this.value = text;
        };

        textBox.focus();
        hiddenField.value = "";
    }
}

function textBoxPaste(textBox) {
    $get('<%= HiddenField1.ClientID %>').value = textBox.value;
    $(textBox).keypress();
}

Bind the RadGrid to your data source dynamically and handle filtering commands.

C#

protected void GriSystem_NeedDataSource(object sender, GridNeedDataSourceEventArgs e)
{
    string ConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
    SqlConnection conn = new SqlConnection(ConnString);
    SqlDataAdapter adapter = new SqlDataAdapter();
    adapter.SelectCommand = new SqlCommand("SELECT [OrderID], [OrderDate], [Freight], [ShipName], [ShipCountry] FROM [Orders]", conn);

    DataTable myDataTable = new DataTable();

    conn.Open();
    try
    {
        adapter.Fill(myDataTable);
    }
    finally
    {
        conn.Close();
    }

    GriSystem.DataSource = myDataTable;
}
protected void GriSystem_ItemCommand(object sender, GridCommandEventArgs e)
{
    if (e.CommandName == RadGrid.FilterCommandName)
    {
        string colName = (e.CommandArgument as Pair).Second.ToString();
        GridColumn col = e.Item.OwnerTableView.GetColumn(colName) as GridColumn;
        TextBox textBox = (e.Item as GridFilteringItem)[colName].Controls[0] as TextBox;

        if (col.FilterDelay != null && textBox != null)
        {
            HiddenField1.Value = textBox.ClientID;
        }
    }
}
protected void GriSystem_ItemCreated(object sender, GridItemEventArgs e)
{
    if (e.Item is GridFilteringItem)
    {
        GridFilteringItem filterItem = e.Item as GridFilteringItem;
        foreach (GridBoundColumn col in filterItem.OwnerTableView.RenderColumns.OfType<GridBoundColumn>().Where(x => x.FilterDelay != null))
        {
            TextBox textBox = filterItem[col.UniqueName].Controls[0] as TextBox;
            textBox.Attributes.Add("onpaste", "textBoxPaste(this);");
        }
    }
}

See Also

• RadGrid Documentation
• Filtering Customization
• RadGrid Filtering with Dropdowns