Custom Columns

• Mar 23, 2021
• 3 minutes to read

The ASPxFileManager control allows you to implement custom columns in Details view mode. To implement a custom column, add an object of the FileManagerDetailsCustomColumn class to the FileManagerFileListDetailsViewSettings.Columns collection.

Note

You cannot set a custom column’s name (the FileManagerDetailsCustomColumn.Name property) to the following values: ‘Extension’, ‘Folder’, ‘FullName’, ‘LastWriteTime’, ‘Length’, ‘Name’, ‘Parent’, ‘RelativeName’, and ‘Location’.

When a custom column cell is rendered, the ASPxFileManager.DetailsViewCustomColumnDisplayText event fires, which allows you to display custom text. You can use the event argument FileManagerDetailsViewCustomColumnDisplayTextEventArgs.Column and FileManagerDetailsViewCustomColumnDisplayTextEventArgs.File (or FileManagerDetailsViewCustomColumnDisplayTextEventArgs.Item) properties to access the currently processed column and file, respectively. The FileManagerDetailsViewCustomColumnDisplayTextEventArgs.DisplayText property allows you to specify the cell display text.

Example

This code sample demonstrates how to populate a file manager custom column with values (file extensions) using the ASPxFileManager.DetailsViewCustomColumnDisplayText

View Example

WebForm1.aspx

<dx:ASPxFileManager ID="ASPxFileManager1" runat="server" Width="800px" Height="400px" OnDetailsViewCustomColumnDisplayText="ASPxFileManager1_DetailsViewCustomColumnDisplayText" OnDetailsViewCustomColumnHeaderFilterFillItems="ASPxFileManager1_DetailsViewCustomColumnHeaderFilterFillItems">
    <Settings RootFolder="~\Files\" ThumbnailFolder="~\Thumb\" />
    <SettingsFileList View="Details">
        <DetailsViewSettings>
            <Columns>
                <dx:FileManagerDetailsColumn Caption=" " FileInfoType="Thumbnail" VisibleIndex="0">
                </dx:FileManagerDetailsColumn>
                <dx:FileManagerDetailsColumn Caption="Name" VisibleIndex="1">
                </dx:FileManagerDetailsColumn>
                <dx:FileManagerDetailsCustomColumn Caption="Extension" Name="FileExtension" VisibleIndex="2" ShowHeaderFilterButton="True">
                </dx:FileManagerDetailsCustomColumn>
            </Columns>
        </DetailsViewSettings>
    </SettingsFileList>
</dx:ASPxFileManager>

WebForm1.aspx.cs

protected void ASPxFileManager1_DetailsViewCustomColumnDisplayText(object source, DevExpress.Web.FileManagerDetailsViewCustomColumnDisplayTextEventArgs e) {
    e.DisplayText = e.File.Extension.Remove(0, 1);
}

WebForm1.aspx.vb

Protected Sub ASPxFileManager1_DetailsViewCustomColumnDisplayText(ByVal source As Object, ByVal e As DevExpress.Web.FileManagerDetailsViewCustomColumnDisplayTextEventArgs)
    e.DisplayText = e.File.Extension.Remove(0, 1)
End Sub

How to Implement a Custom Header Filter for a Custom Column

You can use the FileManagerDetailsCustomColumn.ShowHeaderFilterButton property to specify whether to display a custom column’s header filter. If the property is set to Default, use the FileManagerFileListDetailsViewSettings.ShowHeaderFilterButton property to show the header filter instead.

By default, the header filter displays a list of available column cell values and All, Blanks, and Non blanks items.

You can use the ASPxFileManager.DetailsViewCustomColumnHeaderFilterFillItems event to specify custom header filter items. The FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs.Column event argument property determines the custom column currently being filtered. The FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs.Values property lists the header filter values.

You can use the Clear method to clear the default items. The FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs.AddShowAll method allows you to add the All item to the header filter. To add a custom filter value to the FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs.Values list, use one of the FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs.AddValue overloads.

Example

This code sample demonstrates how to populate a custom column’s header filter with custom items. For this purpose, the ASPxFileManager.DetailsViewCustomColumnHeaderFilterFillItems event is handled.

View Example

WebForm1.aspx

<dx:ASPxFileManager ID="ASPxFileManager1" runat="server" Width="800px" Height="400px" OnDetailsViewCustomColumnDisplayText="ASPxFileManager1_DetailsViewCustomColumnDisplayText" OnDetailsViewCustomColumnHeaderFilterFillItems="ASPxFileManager1_DetailsViewCustomColumnHeaderFilterFillItems">
    <Settings RootFolder="~\Files\" ThumbnailFolder="~\Thumb\" />
    <SettingsFileList View="Details">
        <DetailsViewSettings>
            <Columns>
                <dx:FileManagerDetailsColumn Caption=" " FileInfoType="Thumbnail" VisibleIndex="0">
                </dx:FileManagerDetailsColumn>
                <dx:FileManagerDetailsColumn Caption="Name" VisibleIndex="1">
                </dx:FileManagerDetailsColumn>
                <dx:FileManagerDetailsCustomColumn Caption="Extension" Name="FileExtension" VisibleIndex="2" ShowHeaderFilterButton="True">
                </dx:FileManagerDetailsCustomColumn>
            </Columns>
        </DetailsViewSettings>
    </SettingsFileList>
</dx:ASPxFileManager>

WebForm1.aspx.cs

protected void ASPxFileManager1_DetailsViewCustomColumnHeaderFilterFillItems(object source, DevExpress.Web.FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs e) {
    if (e.Column.Name != "FileExtension") return;
    e.Values.Clear();
    e.AddShowAll();
    e.AddValue("Media Files", string.Empty, "FileExtension = 'avi' or FileExtension = 'mp3' or FileExtension = 'jpg'");
    e.AddValue("Documents", string.Empty, "FileExtension = 'txt' or FileExtension = 'rtf' or FileExtension = 'xml'");
    e.AddValue("Photos", "jpg");
}

WebForm1.aspx.vb

Protected Sub ASPxFileManager1_DetailsViewCustomColumnHeaderFilterFillItems(ByVal source As Object, ByVal e As DevExpress.Web.FileManagerDetailsViewCustomColumnHeaderFilterFillItemsEventArgs)
    If e.Column.Name <> "FileExtension" Then
        Return
    End If
    e.Values.Clear()
    e.AddShowAll()
    e.AddValue("Media Files", String.Empty, "FileExtension = 'avi' or FileExtension = 'mp3' or FileExtension = 'jpg'")
    e.AddValue("Documents", String.Empty, "FileExtension = 'txt' or FileExtension = 'rtf' or FileExtension = 'xml'")
    e.AddValue("Photos", "jpg")
End Sub