Controls / Grid / Troubleshooting

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Known Limitations

This topic summarizes the current RadGrid limitations and unsupported scenarios from all of the topics to forewarn the developer in an early stage of the implementation process.

ViewState

Some functionalities are not supported when the EnableViewState property of RadGrid is set to False. A through explanation can be found in the Optimizing ViewState usage topic.

Grouping

Aggregates only show results for the items on the current Page

When paging is enabled and the last group continues on the next pages, the group aggregates will calculate only the content of the visible items on the current page, and not of the total group records.

Edit Form is not shown when GroupsDefaultExpanded is set to False

A possible workaround is to set the GroupsDefaultExpanded property to True (default: True) and Collapse all the Groups programmatically at the Initial Load.

protected void RadGrid1_PreRender(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        RadGrid grid = (RadGrid)sender;
        List<GridGroupHeaderItem> groupHeaderItems = grid.MasterTableView.GetItems(GridItemType.GroupHeader).Cast<GridGroupHeaderItem>().ToList();

        foreach (GridGroupHeaderItem groupHeaderItem in groupHeaderItems)
        {
            groupHeaderItem.Expanded = false;
        }
    }
}

Protected Sub RadGrid1_PreRender(sender As Object, e As EventArgs)
    If Not Page.IsPostBack Then
        Dim grid As RadGrid = CType(sender, RadGrid)
        Dim grpupHeaderItems As List(Of GridGroupHeaderItem) = grid.MasterTableView.GetItems(GridItemType.GroupHeader).Cast(Of GridGroupHeaderItem)().ToList()

        For Each groupHeaderItem As GridGroupHeaderItem In grpupHeaderItems
            groupHeaderItem.Expanded = False
        Next
    End If
End Sub

Paging

Autogenerated hierarchy with paging is not supported.

Editing

Currently, using Popup Edit Form when both grouping and scrolling are enabled is not supported in RadGrid due to a browser limitation.

Filtering

  • GridDropDownColumn - RadGrid does not include any support for filtering by ListTextField. This limitation is because the filtering mechanism relies on the DataField of the filtered column and for GridDropDownColumn this property specifies the mapping field in the drop-down source.

MultiColumn Headers

The features below are not supported with multicolumn headers:

  • Frozen Columns
  • Show/Hide on the client

Dragging on Mobile

On mobile devices the row drag-drop and scrolling features in the grid are performed by the same touch gesture: dragging of the content area of the grid. This imposes a limitation when both features are enabled on touch devices because it cannot be exclusively determined which one of the two should be performed.

One way to distinguish between scrolling and row drag-drop on mobile devices is to use a GridDragDropColumn - this way the dragging of the rows will be performed only when you drag a row by the icon in the GridDragDropColumn and on the rest of the content area scrolling will be performed.

Client Side Data-binding

A grid bound using client side data-binding improves the performance of RadGrid. However, there are certain limitations, due to this client side model. These are listed below:

  • Data editing and grid editors - since the control is bound on the client, and no subsequent trips are made to the server, the default editors cannot be rendered, and shown, which is the standard behavior, when the grid is bound on the server.
  • Hierarchical structures - with the client side data binding approach for the grid, there is no out-of-the-box support for hierarchical structures.
  • Grouping with client-side binding is not supported. Server binding only should be used in order to achieve grouping.
  • Sorting/Filter expressions - with the standard server side data-binding of the grid control, one could declare/set filter and sorting expressions, which would then be applied to the control - for example declaratively in the aspx markup, or dynamically, in the code-behind section. When using client side data-binding, the same logic can be executed, but in a slightly different manner. The filter/sorting expression can be passed to the relevant page method, which would in turn use it to return the proper data.
  • Exporting - a grid must be bound on the server for exporting to work. With client-side binding you will get an empty file.
  • Templates - the NestedViewTemplate and DetailItemTemplate are server templates and are not supported with client-side binding.

Model Binding

Model binding is not supported when the ViewState of the page is disabled. In order to use the model binding you need to set Page.EnableViewState = "true"

Frozen Columns

There are several limitations that you should have in mind. They are caused by the complexity and specifics of the frozen columns feature, which is implemented by means of hiding and showing columns, instead of actually scrolling them.

  • Resizing with frozen column is not supported.
  • Having hidden columns (with Display property set to false) or hiding/showing columns and frozen columns are not supported at the same time. Hidden columns reappear after scrolling.
  • Merged headers with frozen columns are not supported.
  • When frozen columns are used, tabbing between the textboxes in an inline edit form is not supported out-of-the-box, because the frozen columns will be scrolled together with the non-frozen. In selected scenarios, this functionality can be achieved if you subscribe to the textboxes' focus events and scroll a specific <div> with JavaScript. This <div> has a client ID of <%=RadGridInstance.ClientID%>**_Frozen**. When doing this, you should take into account the current scroll position, and the width of the column that should be hidden/shown.
  • OnScroll client-side event does not fire when horizontal scroll is used for scrolling.
  • Frozen columns are not supported for detail tables of hierarchy grid.

Exporting

There are some limitations in the implementation of the export engine. The sections below list features (content scenarios) that are not supported for the specific export format.

PDF

  • OnGridExporting - this event is usable in many scenarios when you want to modify the output file - for example you may want to add some custom information above RadGrid or when you want to remove/add/replace parts of the content. The only limitation applies to the PDF export because by the time the OnGridExporting event is raised, the PDF is already generated. For more information, please visit the dedicated PDF format topic which introduces the OnPdfExporting event that is designed specifically for this format.
  • Image transparency
  • Right-to-left fonts
  • Nested DIV elements with absolute position
  • Nested DIV elements with specified width or height
  • Automatic text clipping
  • Client-side binding
  • Medium trust

ExcelML

  • When exporting RadGrid with grouping, all groups will be expanded regardless of their actual state.

Biff

  • Hierarchy
  • Grouping
  • Automatic column/row resizing
  • Active links

HTML-Based

  • Embedded images are not supported
  • Exporting invisible RadGrid - to avoid problems with missing content, you should temporarily show RadGrid before export
  • OpenOffice, AbiWord, etc. don't support this standard so they won't show the files properly
  • In theory all Microsoft Office versions from 2000 up might work, although we don't guarantee that any version, prior to 2003 will display the Office HTML formats as expected

Excel Format (HTML-Based)

It is expected to receive the following warning when opening the generated xls file in Microsoft Office 2007:

  • The file you are trying to open, 'Filename.xls', is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted source before opening this file. Do you want to open the file now? *

CSV

  • Hierarchical structure
  • Grouping
  • Exporting invisible RadGrid

Other

Column UniqueName and DataField

The DataField and the UniqueName of a column must contain only letters, numbers and "_". Following the conventions, variables could not start with a number and having auto-generated columns where the column names have a numeric prefix could lead to numerous problems and is not supported scenario.

Change Header Text

When changing the HeaderText for automatically generated columns you should use the DataField property of the column: 

protected void RadGrid1_ColumnCreated(object sender, GridColumnCreatedEventArgs e)
{
    if (e.Column is GridBoundColumn)
    {
        e.Column.HeaderText = ((GridBoundColumn)e.Column).DataField;
    }
}

Protected Sub RadGrid1_ColumnCreated(sender As Object, e As GridColumnCreatedEventArgs)
    If TypeOf e.Column Is GridBoundColumn Then
        e.Column.HeaderText = CType(e.Column, GridBoundColumn).DataField
    End If
End Sub

See Also

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