How to work around bugs in the SPGridView control
SharePoint has a little known web control called SPGridView. This control can give you a SharePoint list-like view of data from any data source you can bind to (from a database or other sources). It also has features to sort, filter and group the data in much the same way users can with SharePoint lists. For more information on how to use this, Paul Robinson has two great posts: SPGridView and SPMenuField: Displaying custom data through SharePoint lists Part 1 and Part 2. In addition, Robert Fridén has a good post on Filtering with SPGridView. However, there are two bugs that can be annoying and cause confusion to users:
- When both filtering and grouping are enabled, the first group title row sometimes disappears.
- When both sorting and filtering are enabled, the sort indicator arrow image will sometimes appear in the wrong column.
Working around either of these bugs requires you to create your own web control based on SPGridView and overriding the CreateChildControls method. Here is the full code listing for the solution to work around both bugs.
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Reflection;
using System.Web.UI;
using System.Web.UI.WebControls;
using Microsoft.SharePoint.WebControls;
namespace AdventuresInConsulting
{
public class GridViewControl : SPGridView
{
protected override int CreateChildControls(System.Collections.IEnumerable dataSource, bool dataBinding)
{
// Due to a bug in SPDataView, we need to reset the private field previousGroupFieldValue so the
// first grouping row title will consistently show up
FieldInfo fieldInfo = typeof(SPGridView).GetField("previousGroupFieldValue",
BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
if (fieldInfo != null)
fieldInfo.SetValue(this, null);
int returnValue = base.CreateChildControls(dataSource, dataBinding);
// Fix up a bug in the SPGridView where it is putting the sort arrow indicator on the wrong
// column if AllowFiltering is true
if (this.AllowFiltering && this.HeaderRow != null && !string.IsNullOrEmpty(this.SortExpression))
{
List<string> filterFields = new List<string>(this.FilterDataFields.Split(','));
if (this.AllowGrouping) filterFields.Insert(0, string.Empty);
for (int i = 0; i < this.HeaderRow.Cells.Count; i++)
{
DataControlFieldHeaderCell cell = this.HeaderRow.Cells[i] as DataControlFieldHeaderCell;
if (cell != null)
{
// Find the sort image control
Image sortImage = null;
foreach (Control c in cell.Controls)
{
sortImage = c as Image;
if (sortImage != null && sortImage.ImageUrl == this.SortDirectionImageUrl)
break;
}
// If this field is filterable, make sure the menu image is correct
if (i < filterFields.Count && filterFields[i].Trim() != string.Empty)
{
// If there is also an image control, remove it (we'll add it back in the right place)
if (sortImage != null) cell.Controls.Remove(sortImage);
// Find the menu control and add or remove the image in there as needed
foreach (Control c in cell.Controls)
{
if (c is Microsoft.SharePoint.WebControls.Menu)
{
Microsoft.SharePoint.WebControls.Menu menu = c as Microsoft.SharePoint.WebControls.Menu;
if (this.SortExpression.Equals(this.Columns[i].SortExpression, StringComparison.InvariantCultureIgnoreCase))
{
// Make sure it has the sort indicator
menu.RightImageUrl = this.SortDirectionImageUrl;
menu.ImageTextSpacing = new Unit("2px", CultureInfo.InvariantCulture);
}
else if (menu.RightImageUrl == this.SortDirectionImageUrl)
{
// Make sure it doesn't have the sort indicator
menu.RightImageUrl = null;
menu.ImageTextSpacing = Unit.Empty;
}
}
}
}
else
{
if (this.SortExpression.Equals(this.Columns[i].SortExpression, StringComparison.InvariantCultureIgnoreCase))
{
// Make sure there is a sort image
if (sortImage == null)
{
sortImage = new Image();
sortImage.ImageUrl = this.SortDirectionImageUrl;
sortImage.Style[HtmlTextWriterStyle.MarginLeft] = "2px";
cell.Controls.Add(sortImage);
}
}
else if (sortImage != null)
{
// Remove the sort image if it exists
cell.Controls.Remove(sortImage);
}
}
}
}
}
return returnValue;
}
}
}
Fixing the group title row disappearance
Making it so that the first group title row doesn't disappear is fairly simple. I noticed that this problem occurred if the filter or sort caused the first group in the new results to be the same as the last group from the previous results. This led me to look at how SPGridView was checking for the start of a new group. Sure enough, it was just checking to see if the value of the group field in the current row was different from the group field value the last time it detected a change. It saves the last group value in a field called previousGroupFieldValue. That value was being preserved between calls (presumably so that paging will work correctly). The easy fix is to reset the last group value. The problem was that the value was accessed through a private field. Of course, thanks to .NET reflection, we won't let that stand in our way. We just grab the FieldInfo for previousGroupFieldValue and then forcibly set the value.
NOTE: you may need to modify this slightly if paging is enabled. You probably only want to reset it if the page has not changed.
Fixing the sort indicator arrow image
Fixing the sort indicator arrow image is the more difficult of the two work arounds. I had hoped to recreate the CreateChildControls method of SPGridView and just avoid the image from coming up in the wrong place. However, it turns out that SPGridView calls its base class CreateChildControls method and there is no way in C# for a derived class to call its base's base class methods. So, rather than trying to recreate a whole chain of CreateChildControls methods, I just let SPGridView put the arrows where it wanted to and then fixed them up later.
The code loops through all of the column headers and looks for the sort indicator image either as a standalone Image control, or as the RightImageUrl of the column menu's title. We remove the image where it doesn't belong and add the image where it does belong.
Note on this bug: the issue arises because enabling grouping causes a hidden column to be added to the front of the grid and the code logic SPGridView uses to decide which column to put the filter indicator on is off by one. You'd think it'd be off to the left, but it is actually off to the right because whoever wrote the code knew there was a hidden column, but they overcompensated for it (kind of feels like being in a car with a kid learning to drive with power steering for the first time).
Comments
Anonymous
March 11, 2009
PingBack from http://www.anith.com/?p=17961Anonymous
May 05, 2009
This is a great article, have been waiting for this fix for ages (and sp2 did not fix it!), thank you! Now only if the filter icon can come up automatically as well :-)Anonymous
June 06, 2009
A really great article. ThanksAnonymous
November 03, 2009
Dear Vladon, It's a nice work you did here. recently I am working with SPGidView and I was wondering about one thing. As the control allows your to use grouping, sorting paging altogether for a databound dataset/table. What if my dataset is too big and I don't want to load it in my memory? How Sharepoint deals this? As I have seen Sharepoint allows me to group lists which has too many rows..around 50,000 items. I have a forum post for this problem here, http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/6be2cc1d-c2d2-431f-a46e-601a5667429d If you know anything regarding this issue...would you please give me a clue? Thanks for your time :)Anonymous
November 08, 2011
Is there a way to use this bug fix for a SPGridView that is built into an application page?Anonymous
November 08, 2011
Jens, this would not work with default pages in SharePoint since they use the built-in grid View. This solution only works using this custom web control on a page.Anonymous
June 19, 2012
Excellent..... This post is really helpful. I have searched on net for whole day to figure out why grouping is not visible in SPGridView. finally find this post and its working fine now. Thanks.