How to recognize applied IsNull filter on a column

[Jakub Sterba]

Greetings,

is it possible to recognize, whether there is filter applied on a column in case of using IsNull or NotIsNull conditions? I did not succeed to apply background color to filter cell, where filter was on. Or is there another way to differentiate filter cell when filter is used for the column?

Thank you very much.

[Daniel]

Hello Jakub,

Please try the following approach:

protected void RadGrid1_ItemCommand(object sender, GridCommandEventArgs e)
{
    if (e.CommandName == RadGrid.FilterCommandName)
    {
        Pair pair = e.CommandArgument as Pair;
        string filterType = pair.First.ToString();
        GridColumn filterCol = RadGrid1.MasterTableView.GetColumn(pair.Second.ToString());

        if (filterType.Contains("IsNull"))
            filterCol.HeaderStyle.CssClass = "myCssClass";
        else
            filterCol.HeaderStyle.CssClass = "rgHeader";
    }
}

Let me know whether this helps.

Regards,
Daniel
the Telerik team

[Jakub Sterba]

Hi,

well, it was a nice try, but there are a few problems. I don't want to change style of header cell, because of style applied, when the column is sorted, but I would like to change style of filter cell, when filtering is applied, because when sorting is applied to the column, the style of the filter cell is not changed. Please, can you navigate me, how to achieve this? I think, there is a problem with prerender event, because it is not fired on the table cell with filter...

Thank you

[Daniel]

Hello Jakub,

I believe the most suitable place to implement that will be the ItemCreated event:

protected void RadGrid1_ItemCreated(object sender, GridItemEventArgs e)
{
    if (e.Item is GridFilteringItem)
        foreach (GridColumn col in RadGrid1.MasterTableView.RenderColumns)
            if (col.SupportsFiltering() && (col.CurrentFilterFunction == GridKnownFunction.IsNull || col.CurrentFilterFunction == GridKnownFunction.NotIsNull))
                (e.Item as GridFilteringItem)[col.UniqueName].BackColor = System.Drawing.Color.Red;
}

Regards,
Daniel
the Telerik team

[Jakub Sterba]

Hi,

works like a charm now. First of all, it was one postback behind. Then I found, it was my fault, because I use my own datasourceviews and Rebind() was to be called. Now it's all ok.

Thank you very much.

[Igor]

Hi Daniel, your solution works, but not on all columns. If a column is also sorted, the background is not set red. Ist something missed here?

Thank you,

Igor

[Daniel]

Hello Igor,

It is hard to guess what is wrong in your scenario. Could you please test the attached demo where I tried to reproduce the problem? Let me know if I'm leaving out something.

Kind regards,
Daniel
the Telerik team

[Igor]

Hi Daniel,

thank you, with your example I can reproduce my scenario. I want to set the background color below the column header when a filter is active. I have done  a little modification of your code, here:

<script type="text/C#" runat="server">
        protected void Page_Init(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                GridSortingSettings sortingSettings = RadGrid1.SortingSettings;
                sortingSettings.SortedBackColor = System.Drawing.Color.Transparent;
            }
        }

        protected void RadGrid1_ItemCreated(object sender, GridItemEventArgs e)
        {
            if (e.Item is GridFilteringItem)
            {
                System.Drawing.Color markColor = System.Drawing.Color.BlanchedAlmond;

                foreach (GridColumn col in RadGrid1.MasterTableView.RenderColumns)
                {
                    if (col.SupportsFiltering() &&
                        col.CurrentFilterFunction != GridKnownFunction.NoFilter)
                    {
                        (e.Item as GridFilteringItem)[col.UniqueName].BackColor = markColor;
                    }

                }
            }
        }

    </script>

it seam that 

sortingSettings.SortedBackColor = System.Drawing.Color.Transparent;

make the custom filter background color disappear when the column is sorted. I can remove the transparent color to the  SortedBackColor property, but the sorted grid column background is to strong. Do you know another way to mark the filtered column without changing the transparent sorted background color?

Best regards,
Igor     
 

[Daniel]

Hello Igor,

Of course it is not possible to have two background colors on a single cell. Instead of setting the background color in code-behind, I recommend that you use a css rule:

<style type="text/css">
    .RadGrid table.rgMasterTable td.rgSorted
    {
        background-color: blue;
    }
</style>

Regards,
Daniel
the Telerik team

[Igor]

perfect, it works like a charm.
Thank you, Igor