Thanks Mike for the prompt response.

Here is very simple sample code I put together that illustrates the problem. Without resetting DataSource it runs for ~8 seconds. When you first set DataSource to null, do your changes and set it back to ultraDataSource it takes less than a second.

//ultraGrid1.DataSource = null;

this.ultraGrid1.BeginUpdate();
this.ultraGrid1.SuspendRowSynchronization();
try
{
    UltraDataRow row = ultraDataSource1.Rows.Add(new object[] { "Data1", "Data2", "Data3", "Data4", "Data5" });
   
    for (int i = 0; i < 30; i++)
    {
        UltraDataBand band = ultraDataSource1.Band.ChildBands.Add(i.ToString());
        //don't know if there is an easier way to inherit parent band's columns
        foreach (UltraDataColumn column in ultraDataSource1.Band.Columns)
            band.Columns.Add(column.Key, column.DataType);

        UltraDataRow row2 = row.GetChildRows(band).Add(new object[] { "BandA", "Data2", "Data3", "Data4", "Data5" });               
    }

    //ultraGrid1.DataSource = ultraDataSource1;
}
finally
{
    this.ultraGrid1.ResumeRowSynchronization();
    this.ultraGrid1.EndUpdate();
}

This code is very strange. I ran it, and it is indeed very slow. But I think the problem is that you are creating a child band for every parent row. Why are you doing that? Is there some reason you need to create an entirely different band for each row in the parent band?

I was just trying to reduce my actual code to a small  sample that reproduces the problem. In my real code I have an hierarchical structure with a lot of nested levels and a lot more rows so the problem is even more acute.

I managed to get decent performance by detaching and then attaching back my datasource and Saving and loading back my DisplayLayout so that I still have column formatting, etc. One weird thing is that saving/loading back of DisplayLayout does not preserve Visible Header index - after DisplayLayout.Load my columns are in the wrong order.

Lev said:

I was just trying to reduce my actual code to a small  sample that reproduces the problem. In my real code I have an hierarchical structure with a lot of nested levels and a lot more rows so the problem is even more acute.

Well, the sample you have here is not really representative of the real issue, then, so it's not really much good to us in terms of figuring out what's going on here.

Are you doing something similar in your real application - and by that I mean, are you adding a large number of bands like your sample is doing? If so, then that might explain what's happening here. If you have a very large, complex, hierarchy of data with a lots of levels, then the BindingManager in DotNet is going to have serious performance issues. These issues would not occur when the data is not bound to the grid, because without the grid, the BindingManagers would not be created up front.

The sample I provided is very much representative of the issue - that was the whole point of creating the sample. Sounds like it's a problem inherent in the design of ultragrid. UltraDataSource by itself has no  problems with large number of bands, and BTW 30 is NOT a large number of bands, ultragrid by itself has no problem with that number of bands - it's the combination that is not working well together.

So would you suggest I do what I do right now - unbind ultragrid, do changes to datasrouce and bind it back? Or is there a better solution?

30 is quite a large number of bands in my opinion. In my experience, the sheer number of BindingManagers will cause serious performance problems in Visual Studio, regardless of what kind of data source you are using, when you reach about 8 bands.

Of course, there is no problem with UltraDataSource by itself, because when you just have the UltraDataSource and it's not bound to anything, no BindingManagers are created. The BindingManagers are created by the grid when you bind it.

Are you saying that there is some other data source in which you can add 30 bands while it's bound to the grid and it's not a problem? If so, what data source are you referring to?

Lev said:

So would you suggest I do what I do right now - unbind ultragrid, do changes to datasrouce and bind it back? Or is there a better solution?

That seems like a reasonable way around the issue. It probably works better because the grid doesn't have to respond to each individual notification from every BindingManager every time you add a band - it only has to create everything once.

Thanks Mike,

8 Bands is a large number when you pull data from joined tables in database - I agree with you on that one, i haven't seen many queries that join more than 8 tables.

When you populate your own UltraDataSource with adhoc data or your data has a recursive relationship you can very easily have very large number of bands. In my application I have a recursive parent/child relationship with many levels of nesting, and each parent level requires creation of a new band.

I guess I'll stick with unbind, populate and bind again approach for now.