Grouping header is null?

[Mark Smith]

Hi

We're trying to group by a field called CompanyName. The grid seems to show the group but it creates a group per record. I tried hooked into the GroupSummaryEvaluate event and when I look at the e.Value it's null?

If I remove the grouping I can see that CompanyName has values

Why is it showing "CompanyName : " instead of "CompanyName : Some Company Name" ?

[Emanuel Varga]

Hello Mark,

Could you please tell me what is the type for the CompanyName? string? is it a data bound column?

For more info on grouping please take a look at this help article.

If you are still having problems, please create a small sample and post it here and i will do my best to help you solve this issue.

Best Regards,
Emanuel Varga

[Renate]

Hello Emanuael,

I have a similar problem as Mark, but for custom grouping only:

1. grid.EnableCustomGrouping= true;

2. in grid_CustomGrouping  a new GroupKey is set for 1 column because I want to sort by another (hidden) column:
   
    e.GroupKey = <value_of_some_other_column>;

3. In the grid_GroupSummaryEvaluate event

    a) e.Value and e.Group.Header are set for non-custom-group columns but
    b) both are null for the custom-group column, so the group header only consists of the column name plus ':',
         e.g. "CompanyName : " instead of "CompanyName : Some Company Name"
  
Is there anything else I have to do in the grid_CustomGrouping event?

Hope you can help me with ths

best regards

renu

[Julian Benkov]

Hi Renate,

In this custom grouping scenario you can use e.Group.Key value to format the header in GorupSummaryEvaluate event handler. Here is a codebase of our Demo application for custom grouping:

public partial class Form1 : ExamplesForm
    {
        public Form1()
        {
            InitializeComponent();

            this.radGridView.EnableGrouping = true;
            this.radGridView.EnableCustomGrouping = true;
            this.radGridView.ShowGroupedColumns = true;

            this.radGridView.GroupSummaryEvaluate += new GroupSummaryEvaluateEventHandler(radGridView_GroupSummaryEvaluate);
            this.radGridView.ViewRowFormatting += new RowFormattingEventHandler(radGridView_ViewRowFormatting);
        }

        private void SetConditions()
        {
            ConditionalFormattingObject c3 = new ConditionalFormattingObject("Grey, applied to cell", ConditionTypes.NotEqual, "Germany", "", false);
            c3.RowBackColor = Color.FromArgb(169, 183, 201);
            c3.CellBackColor = Color.FromArgb(169, 183, 201);
            this.radGridView.Columns["Country"].ConditionalFormattingObjectList.Add(c3);

            ConditionalFormattingObject c1 = new ConditionalFormattingObject("Blue , applied to cell", ConditionTypes.Equal, "Germany", "", false);
            c1.RowBackColor = Color.FromArgb(163, 191, 226);
            c1.CellBackColor = Color.FromArgb(163, 191, 226);
            this.radGridView.Columns["Country"].ConditionalFormattingObjectList.Add(c1);

            ConditionalFormattingObject c2 = new ConditionalFormattingObject("LightPurple, applied to cell", ConditionTypes.Equal, "France", "", false);
            c2.RowBackColor = Color.FromArgb(212, 210, 241);
            c2.CellBackColor = Color.FromArgb(212, 210, 241);
            this.radGridView.Columns["Country"].ConditionalFormattingObjectList.Add(c2);
        }

        private void radGridView1_CustomGrouping(object sender, GridViewCustomGroupingEventArgs e)
        {
            if (this.UseDefaultGrouping(e.Level))
            {
                e.Handled = false;
                return;
            }

            int color = Color.White.ToArgb();
            int columnIndex = this.radGridView.Columns["Country"].Index;
            ConditionalFormattingObjectCollection conditions = this.radGridView.Columns[columnIndex].ConditionalFormattingObjectList;

            for (int i = 0; i < conditions.Count; i++)
            {
                if (conditions[i].Evaluate(e.Row, this.radGridView.Columns["Country"]))
                {
                    color = conditions[i].CellBackColor.ToArgb();
                }
            }

            e.GroupKey = color;
        }

        private bool UseDefaultGrouping(int level)
        {
            GroupDescriptor groupDescriptor = this.radGridView.GroupDescriptors[level];
            for (int i = 0; i < groupDescriptor.GroupNames.Count; i++)
            {
                if (groupDescriptor.GroupNames[i].PropertyName.Equals("Country", StringComparison.InvariantCultureIgnoreCase))
                {
                    return false;
                }
            }

            return true;
        }

        void radGridView_ViewRowFormatting(object sender, RowFormattingEventArgs e)
        {
            GridViewGroupRowInfo groupRow = e.RowElement.RowInfo as GridViewGroupRowInfo;
            if (groupRow != null && groupRow.Group.Key is int)
            {
                e.RowElement.BackColor = Color.FromArgb((int)groupRow.Group.Key);
            }
        }

        void radGridView_GroupSummaryEvaluate(object sender, GroupSummaryEvaluationEventArgs e)
        {
            if (this.UseDefaultGrouping(e.Group.Level))
            {
                return;
            }

            e.FormatString = this.GetColorName(e.Group.Key.ToString());
        }

        private string GetColorName(string p)
        {
            switch (p)
            {
                case "-6045726":
                    return "Blue";
                case "-5654583":
                    return "Grey";
                case "-2829583":
                    return "LightPurple";
                default:
                    return "White";
            }
        }

        private void OnFormLoad(object sender, EventArgs e)
        {
            this.customersTableAdapter.Fill(this.nwindRadGridView.Customers);

            this.SetConditions();
            this.radGridView.GroupDescriptors.Expression = "Country";

            this.SelectedControl = this.radGridView;
        }

        protected override string GetExampleDefaultTheme()
        {
            return "ControlDefault";
        }
    }

I hope this helps. Let me know if you need further assistance.

Greetings,
Julian Benkov
the Telerik team