Formatting with Events

• Nov 02, 2021
• 3 minutes to read

ASPxGridView has three events that allow you to display custom text for individual group rows, data, and summary cells.

CustomColumnDisplayText Event

The ASPxGridView.CustomColumnDisplayText event allows you to define custom display text for any cell.

Example

This example demonstrates how to display the “empty” string within the Units On Order column’s cells if they contain zero values.

The image below shows the result:

C#

protected void ASPxGridView2_CustomColumnDisplayText(object sender,
    DevExpress.Web.ASPxGridViewColumnDisplayTextEventArgs e) {
    if (e.Column.FieldName != "UnitsOnOrder") return;
    if (Convert.ToInt32(e.Value) == 0)
        e.DisplayText = "empty";
}

VB.NET

Protected Sub ASPxGridView1_CustomColumnDisplayText(ByVal sender As Object,_
    ByVal e As DevExpress.Web.ASPxGridViewColumnDisplayTextEventArgs)_
    Handles ASPxGridView1.CustomColumnDisplayText
    If e.Column.FieldName = "UnitsOnOrder" Then
        If Convert.ToInt32(e.Value) = 0 Then
            e.DisplayText = "empty"
        End If
    End If
End Sub

CustomGroupDisplayText Event

The ASPxGridView.CustomGroupDisplayText event allows you to specify custom content for individual group rows.

Example

In the example below, the grid raises the CustomColumnGroup and CustomColumnSort events to apply a custom grouping and sort algorithm to the Unit Price column.

The control also raises the CustomGroupDisplayText event to change the text within group rows.

ASPX

<dx:ASPxGridView ID="grid" runat="server" AutoGenerateColumns="False" KeyFieldName="ProductID" 
    OnCustomColumnGroup="grid_CustomColumnGroup" 
    OnCustomColumnSort="grid_CustomColumnSort" 
    OnCustomGroupDisplayText="grid_CustomGroupDisplayText">
    <GroupSummary>
        <dx:ASPxSummaryItem SummaryType="Count" />
    </GroupSummary>
    <Columns>
        <dx:GridViewDataTextColumn FieldName="ProductID" ReadOnly="True" VisibleIndex="0">
            <EditFormSettings Visible="False" />
        </dx:GridViewDataTextColumn>
        <dx:GridViewDataTextColumn FieldName="ProductName" VisibleIndex="1" />
        <dx:GridViewDataTextColumn FieldName="UnitPrice" VisibleIndex="2" GroupIndex="0" SortIndex="0"
            SortOrder="Ascending">
            <PropertiesTextEdit DisplayFormatString="c" />
            <Settings AllowDragDrop="False" SortMode="Custom" />
        </dx:GridViewDataTextColumn>
        <dx:GridViewDataCheckColumn FieldName="Discontinued" VisibleIndex="3" />
    </Columns>
    <Settings ShowGroupedColumns="True" ShowGroupPanel="True" />
</dx:ASPxGridView>

C#

protected void grid_CustomColumnSort(object sender, DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs e) {
    CompareColumnValues(e);
}

protected void grid_CustomColumnGroup(object sender, DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs e) {
    CompareColumnValues(e);
}

private void CompareColumnValues(DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs e) {
    if(e.Column.FieldName == "UnitPrice") {
        int res = 0;
        double x = Math.Floor(Convert.ToDouble(e.Value1) / 10);
        double y = Math.Floor(Convert.ToDouble(e.Value2) / 10);
        res = Comparer.Default.Compare(x, y);
        if(res < 0) res = -1;
        else if(res > 0) res = 1;
        if(res == 0 || (x > 9 && y > 9)) res = 0;

        e.Result = res;
        e.Handled = true;
    }
}

protected void grid_CustomGroupDisplayText(object sender, DevExpress.Web.ASPxGridView.ASPxGridViewColumnDisplayTextEventArgs e) {
    if(e.Column.FieldName == "UnitPrice") {
        double d = Math.Floor(Convert.ToDouble(e.Value) / 10);
        string displayText = string.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10);
        if(d > 9) displayText = string.Format(">= {0:c} ", 100);
        e.DisplayText = displayText;
    }
}

VB.NET

Protected Sub grid_CustomColumnSort(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs)
    CompareColumnValues(e)
End Sub

Protected Sub grid_CustomColumnGroup(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs)
    CompareColumnValues(e)
End Sub

Private Sub CompareColumnValues(ByVal e As DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs)
    If e.Column.FieldName = "UnitPrice" Then
        Dim res As Integer = 0
        Dim x As Double = Math.Floor(Convert.ToDouble(e.Value1) / 10)
        Dim y As Double = Math.Floor(Convert.ToDouble(e.Value2) / 10)
        res = Comparer.[Default].Compare(x, y)

        If res < 0 Then
            res = -1
        ElseIf res > 0 Then
            res = 1
        End If

        If res = 0 OrElse (x > 9 AndAlso y > 9) Then res = 0
        e.Result = res
        e.Handled = True
    End If
End Sub

Protected Sub grid_CustomGroupDisplayText(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.ASPxGridViewColumnDisplayTextEventArgs)
    If e.Column.FieldName = "UnitPrice" Then
        Dim d As Double = Math.Floor(Convert.ToDouble(e.Value) / 10)
        Dim displayText As String = String.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10)
        If d > 9 Then displayText = String.Format(">= {0:c} ", 100)
        e.DisplayText = displayText
    End If
End Sub

SummaryDisplayText Event

The ASPxGridView.SummaryDisplayText event allows you to specify custom display text for any total or group summary value.