How to make expression column calculate based on the current visible columns

[James Blibo]

I have a situation like this. I have three columns (A, B, and C) and a expression columns that is defines as A + B + C.

expr-----colA---colB---colC
60 ----- 10 --- 20 --- 30

when the visible columns is colA and colC, I want the expression column to calculate based on only columns A and C like below

expr-----colA---colC
40 ----- 10 --- 30


Is there a way to do this? I am trying to achieve something like the RecordFilter, but only apply that to columns.

[Administrator]

Hi James,

You can handle the VisibleColumn.Changing event and set the ExpressionDescriptor.Express property to your required expression. Here is a code snippet to show this.

private void VisibleColumns_Changing(object sender, Syncfusion.Collections.ListPropertyChangedEventArgs e)
{
if( e.Action == Syncfusion.Collections.ListPropertyChangedType.Add)
{
ExpressionFieldDescriptor ed = this.gridGroupingControl1.TableDescriptor.ExpressionFields["ExpressionColumn"];
GridVisibleColumnDescriptor column = e.Item as GridVisibleColumnDescriptor;
if( ed.Expression.IndexOf(column.Name) == -1)
{
string sOldValue = string.Format("+ [{0}]",column.Name);
ed.Expression += sOldValue;
}
}
else if( e.Action == Syncfusion.Collections.ListPropertyChangedType.Remove)
{
ExpressionFieldDescriptor ed = this.gridGroupingControl1.TableDescriptor.ExpressionFields["ExpressionColumn"];
GridVisibleColumnDescriptor column = e.Item as GridVisibleColumnDescriptor;
if( ed.Expression.IndexOf(column.Name) != -1)
{
string sOldValue = string.Format("+ [{0}]",column.Name);
string Expression = ed.Expression.Replace(sOldValue,string.Empty);
if( Expression.Equals(ed.Expression) )
{
Expression = ed.Expression.Replace(string.Format("[{0}] +",column.Name),string.Empty);
}
ed.Expression = Expression;
}
}
}

Here is a sample.
GGCExpressionField.zip

Best Regards,
Haneef

[James Blibo]

Are you kidding me? I was about to create different permutations of expression fields to accomplish the same thing. You guys are the greatest!

thx

[James Blibo]

I have a couple of summary columns above the header. When I toggle (show/hide) soecific visible columns, I expect the summary column above each specific visible columns to also show/hide, depending on which visible columns they're align to; however, this is not happening... what gives?

[James Blibo]

got it to work... please disregard post