Expression Editor, when integrated with grid, allows calculating column data for unbound columns of FlexGrid.

To allow expressions to be used for generating data for unbound columns of FlexGrid, you can create a class that inherits C1FlexGrid class and implements ISupportExpressions interface. Then add Expression Editor on unbound columns of the new FlexGrid, where you need to display calculated values.

The following image exhibits FlexGrid control, demonstrating column calculation using expressions.

 The following code demonstrates column calculation on FlexGrid columns through expressions.

1. Create a class that inherits C1FlexGrid and implements ISupportExpressions interface, as shown in the following code snippet.
   • VB
   • C#

   • VB

   Public Class FlexGridEE
       Inherits C1FlexGrid
       Implements ISupportExpressions
   
       Public Sub New()
           MyBase.New()
           ExpressionEditors = New ExpressionEditorCollection(Me)
       End Sub
   
       ' ISupportExpressions
   
       Public Sub SetCellValue(row As Integer, colName As String,
                               value As Object) Implements 
                  ISupportExpressions.SetCellValue
           Me(row, colName) = value
       End Sub
   
       Public Overloads ReadOnly Property ExpressionEditors()
                   As ExpressionEditorCollection Implements 
              ISupportExpressions.ExpressionEditors
   
       Private Property ISupportExpressions_ItemsSource
       As IEnumerable Implements ISupportExpressions.ItemsSource
           Get
               Return Me.ItemsSource
           End Get
           Set(value As IEnumerable)
               Me.ItemsSource = value
           End Set
       End Property
   
   End Class
   

   • C#

   public class FlexGridEE : C1FlexGrid, ISupportExpressions
   {
       
       public FlexGridEE() : base()
       {
           ExpressionEditors = new ExpressionEditorCollection(this);
       }
              
       // Using ISupportExpressions
       public void SetCellValue(int row, string colName, object value)
       {
           this[row, colName] = value;
       }
       public ExpressionEditorCollection ExpressionEditors { get; }
       
   }
   

2. Now, add expression editor on unbound columns of the new FlexGrid, as shown in the following code snippet.
   • VB
   • C#

   • VB

   Dim c1ExpressionEditor1 As New C1ExpressionEditor()
   Dim c1ExpressionEditor2 As New C1ExpressionEditor()
   c1ExpressionEditor1.Expression = "[Price] + [Cost]"
   c1ExpressionEditor2.Expression = "[Price] * 0.8 + [Cost]"
   flexGrid.ExpressionEditors.Add("CustomField1", c1ExpressionEditor1)
   flexGrid.ExpressionEditors.Add("CustomField2", c1ExpressionEditor2)
   

   • C#

   C1ExpressionEditor c1ExpressionEditor1 = new C1ExpressionEditor();
   C1ExpressionEditor c1ExpressionEditor2 = new C1ExpressionEditor();
   c1ExpressionEditor1.Expression = "[Price] + [Cost]";
   c1ExpressionEditor2.Expression = "[Price] * 0.8 + [Cost]";
   flexGrid.ExpressionEditors.Add("CustomField1", c1ExpressionEditor1);
   flexGrid.ExpressionEditors.Add("CustomField2", c1ExpressionEditor2);
   

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