SPGridview Filter is being cleared on paging events

Question

I have an SPGridView, SPGridViewPager and an Object data source that are all pre-defined in the ascx.

The grid are just populated by the code behind with the object data source.

The grid view is inside an update panel

My issue is when i filter the view, and go to the next page, the filter is persisted but I cannot clear the Filter anymore the 'Clear filter' for the column in the view is disabled.

I also set the FilterExpression on Pre Render.

    protected override void OnPreRender(EventArgs e)
    {
         base.OnPreRender(e);
        if (!string.IsNullOrEmpty(this.FilterExpression))
        {
            this.MyDataSource.FilterExpression =  this.FilterExpression;
            this.ViewState["FilterExpression"] = this.FilterExpression;
        }
    }

Answer 1

In case someone stumbles upon the same issue, i have solved it by setting the FilterFieldName attribute on my controls Pre Render event:

FilterFieldName property of the gridview cannot be set directly you have to set it by using "Attribute".

    if (!string.IsNullOrEmpty(this.FilterExpression))
        {
            string[] columns = this.FilterExpression.Split(new[] { "like" }, StringSplitOptions.RemoveEmptyEntries);
            if (columns != null)
            {
                string[] columnFieldName = columns[0].Split(new[] { "(" }, StringSplitOptions.RemoveEmptyEntries);
                string filteringColumn = columnFieldName[0].ToString();
                this.MyGridView.Attributes["FilterFieldName"] = filteringColumn.Trim();

            }
        }