Yeah, BasedOnDataType essentially differentiates between numeric columns and Date columns, since summaries like Sum don't make sense for dates. 

I, too, was surprised to discover the BasedOnDataType completely removes the summary icon for Strings. I don't know for sure why it was done that way. But if I had to guess, I imagine the thinking goes something along the lines of - if you want a Count of the rows in the grid, you can get it from ANY column so having only a single option for string columns isn't very useful.

I noticed yesterday while trying different options that for columns with data types of Boolean or String that Average and Sum were disabled. The code example from yesterday pointed  me in the direction I need to mimic that. The controls did get disabled but once the summary form was shown the controls were no longer disabled. I assumed the shown or load event for the form was overriding the properties. The code you provided will fix the issue with shown overriding my property changes. Plus the added reliability of using the control names instead of the text because the names of the controls are less likely to change. I tested the code in my current project and works as expected. Thanks. I am a little surprised that setting summaries to be BasedOnDataType removes the summary button for strings and boolean's. I would have thought Count would be available for all data types because it is not data related. I am sure there is a reason for it. Thanks for your time.

A couple things about this approach. 

First, the dialog typically disables the checkboxes, it doesn't remove them. So removing them might have unintended consequences if the dialog assumes that the controls are still there or gets re-used. 

Also, I would rely on the Text, since that can be changed via localization. 

Lastly, using indexes for controls (like this code does in order to get the panel) may not always be reliable, since the structure of the dialog might change. It would be better overall and more stable to use the names of those controls. 

Here's an alternative solution that I think will be a littler more solid and reliable and less subject to breakage. 

        List<Control> checkboxesToDisable;
        private void UltraGrid1_BeforeSummaryDialog(object sender, BeforeSummaryDialogEventArgs e)
        {
            if (e.Column.DataType == typeof(string))
            {
                Control sumCheckBox = e.SummaryDialog.Controls.Find("sumCheckBox", true)[0];
                Control averageCheckBox = e.SummaryDialog.Controls.Find("averageCheckBox", true)[0];
                Control maximumCheckBox = e.SummaryDialog.Controls.Find("maximumCheckBox", true)[0];
                Control minimumCheckBox = e.SummaryDialog.Controls.Find("minimumCheckBox", true)[0];
                Control countCheckBox = e.SummaryDialog.Controls.Find("countCheckBox", true)[0];

                // Decide which checkboxes to include here. 
                this.checkboxesToDisable = new List<Control>() { sumCheckBox, averageCheckBox, maximumCheckBox, minimumCheckBox, countCheckBox };

                e.SummaryDialog.Shown += this.SummaryDialog_Shown;
                
            }
        }

        private void SummaryDialog_Shown(object sender, EventArgs e)
        {
            ((Form)sender).Shown -= this.SummaryDialog_Shown;
            foreach (Control control in checkboxesToDisable)
            {
                control.Enabled = false;
            }
        }

This should work great. Thanks.

Hello Michael,

My apologies, I must have missed the summary question in your original post.

At the moment, there is unfortunately no property on the columns to directly control which summaries are available in the summary dialog that shows up. There are a couple of potential alternatives in this case though.

The first alternative I can recommend is to set the UltraGridLayout.Override.AllowRowSummaries property to AllowRowSummaries.BasedOnDataType. For string columns, though, this will actually disable the summaries.

The other alternatives in this case involve handling the BeforeSummaryDialog event of the UltraGrid. The event arguments of this event will net you the summary dialog that is opening, and you can either dig into the Controls collection of this dialog and remove elements from it or cancel the event and show your own dialog to act as the summary selection dialog. The following code snippet demonstrates how you can remove a checkbox from the summary dialog in the BeforeSummaryDialog event:

        private void UltraGrid1_BeforeSummaryDialog(object sender, BeforeSummaryDialogEventArgs e)
        {            
            var panel = e.SummaryDialog.Controls[0].Controls[0].Controls[1];

            List<CheckBox> checkboxesToRemove = new List<CheckBox>();
            foreach(var x in panel.Controls)
            {
                string type = x.GetType().Name;

                if(x is CheckBox)
                {
                    var checkbox = x as CheckBox;
                    
                    if(checkbox.Text == "Average")
                    {
                        checkboxesToRemove.Add(checkbox);
                    }
                }
            }

            foreach(CheckBox check in checkboxesToRemove)
            {
                panel.Controls.Remove(check);
            }            
        }

Please let me know if you have any other questions or concerns.