Custom Group by Name

When you group a column in WebHierarchicalDataGrid™, the rows are grouped based on the cell’s value in that column. You can change this default behavior and group rows according to a custom comparison. To perform custom grouping functionality, you must implement the generic GroupEqualityComparer abstract class. After doing so, assign an instance of your custom comparer class to the GroupComparer property of a ColumnGroupingSetting object.

The GroupEqualityComparer class requires you to implement two methods: Equals and GroupName. The Equals method is where you provide your custom logic for comparison, whereas the GroupName method returns a string for the group row.

The following code shows you how to group by only the first letter of an Employee’s last name.

In Visual Basic:

Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
    Me.WebHierarchicalDataGrid1.GroupingSettings.GroupedColumns.Add("LastName")
    Dim setting As New ColumnGroupingSetting()
    setting.ColumnKey = "LastName"
    setting.GroupComparer = New AlphabetGroupComparer()
    Me.WebHierarchicalDataGrid1.GroupingSettings.ColumnSettings.Add(setting)
End Sub
Public Class AlphabetGroupComparer
    Inherits GroupEqualityComparer(Of String)
    Public Overloads Overrides Function Equals(ByVal x As String, ByVal y As String) As Boolean
        If x.Substring(0, 1).ToLower() = y.Substring(0, 1).ToLower() Then
            Return True
        End If
        Return False
    End Function
    Public Overloads Overrides Function GroupName(ByVal value As String) As String
        If value.Length = 0 Then
            Return String.Empty
        End If
        Return value.Substring(0, 1).ToUpper()
    End Function
End Class

In C#:

protected void Page_Init(object sender, EventArgs e)
{
    this.WebHierarchicalDataGrid1.GroupingSettings.GroupedColumns.Add("LastName");
    ColumnGroupingSetting setting = new ColumnGroupingSetting();
    setting.ColumnKey = "LastName";
    setting.GroupComparer = new AlphabetGroupComparer();
    this.WebHierarchicalDataGrid1.GroupingSettings.ColumnSettings.Add(setting);
}
public class AlphabetGroupComparer : GroupEqualityComparer<string>
{
    public override bool Equals(string x, string y)
    {
        if (x.Substring(0, 1).ToLower() == y.Substring(0, 1).ToLower())
            return true;
        return false;
    }
    public override string GroupName(string value)
    {
        if (value.Length == 0)
            return string.Empty;
        return value.Substring(0, 1).ToUpper();
    }
}

WebHierarchcialDataGrid CustomGroupByName 01.png

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Custom Group by Name

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