Formatting via Events

• Dec 17, 2020
• 4 minutes to read

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

CustomColumnDisplayText Event

ASPxGridView.CustomColumnDisplayText - enables you to provide 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

ASPxGridView.CustomGroupDisplayText - allows you to provide custom content for individual group rows.

Example

This example demonstrates how to implement custom grouping. The data is grouped by the ‘Unit Price’ column, and the column’s rows that have values between 0 and 10 are combined into a single group. Rows whose values fall between 10 and 20 are combined into another group, etc.

The ‘Unit Price’ column’s GridDataColumnSettings.SortMode property is set to ‘Custom’, and the ASPxGridView.CustomColumnGroup and ASPxGridView.CustomColumnSort events are handled identically.

Additionally, the ASPxGridView.CustomGroupDisplayText event is handled to replace the default text displayed within group rows.

The image below shows the result.

Note

Refer to the How to implement custom grouping logic for ASPxGridView columns online example to review how it works.

ASPX

<dx:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False" 
    DataSourceID="AccessDataSource1" KeyFieldName="ProductID" 
    OnCustomColumnGroup="ASPxGridView1_CustomColumnGroup" 
    OnCustomColumnSort="ASPxGridView1_CustomColumnSort" 
    OnCustomGroupDisplayText="ASPxGridView1_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>

        <dx:GridViewDataTextColumn FieldName="UnitPrice" VisibleIndex="2" 
            GroupIndex="0" SortIndex="0" SortOrder="Ascending">
            <PropertiesTextEdit DisplayFormatString="c">
            </PropertiesTextEdit>
            <Settings AllowDragDrop="False" SortMode="Custom" />
        </dx:GridViewDataTextColumn>

        <dx:GridViewDataCheckColumn FieldName="Discontinued" VisibleIndex="3">
        </dx:GridViewDataCheckColumn>
    </Columns>

    <Settings ShowGroupedColumns="True" ShowGroupPanel="True" />
</dx:ASPxGridView>

C#

protected void ASPxGridView1_CustomColumnSort(object sender, DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs e){
    CompareColumnValues(e);
}

protected void ASPxGridView1_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 ASPxGridView1_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

Class SurroundingClass
    Protected Sub ASPxGridView1_CustomColumnSort(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridView.CustomColumnSortEventArgs)
        CompareColumnValues(e)
    End Sub

    Protected Sub ASPxGridView1_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 ASPxGridView1_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
End Class

SummaryDisplayText Event

ASPxGridView.SummaryDisplayText - enables custom display text to be provided for any total or group summary value.