venpisi said:

Set the CellMultiLine property to true. In run time assign string value with format that includes /n.

Thanks, venpisi, but this is not what I want. Since the input value is of DateTime type, I can use the Format property of the column to set how the text is actually displayed.

For example:

I can set the Format property to "yyyy-MM-dd hh:mm" to display the DateTime as 2008-11-7 12:00 or I can set it to "hh:mm" to display the DateTime as "12:00"

My current problem is I want to insert something to represent an Enter between the Date and the Time. I guessed it is "\n", but it is not. In this case I don't have to loop all rows in the grid to set their format.

Thanks.

Do you need the column to be editable and have a date dropdown? If so, then I don't think this can be done. The DateTime editor in the grid does not support multi-line text. 

If you don't need editing and just want to display the date, then you can do something like this: 

            rootBand.Columns["DateTime 1"].Style = Infragistics.Win.UltraWinGrid.ColumnStyle.Edit;
            rootBand.Columns["DateTime 1"].CellActivation = Activation.NoEdit;
            rootBand.Columns["DateTime 1"].CellMultiLine = DefaultableBoolean.True;
            rootBand.Columns["DateTime 1"].Format = "yyyy-MM-dd\nhh:mm";