ColumnView.CustomUnboundColumnData Event
Allows you to supply data to cells in visible unbound columns, and save values entered by users.
Namespace: DevExpress.XtraGrid.Views.Base
Assembly: DevExpress.XtraGrid.v24.2.dll
Declaration
Event Data
The CustomUnboundColumnData event's data class is CustomColumnDataEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Column | Gets the unbound column currently being processed. |
| IsGetData | Gets whether the column/row needs to be populated with cell values. Inherited from UnboundColumnDataEventArgs. |
| IsSetData | Gets whether a cell value changed and data needs to be posted to a data source. Inherited from UnboundColumnDataEventArgs. |
| ListSourceRowIndex | Gets the current row’s index in the data source. |
| Row | Gets the currently processed row. |
| Value | Gets or sets a cell value in an unbound column. Inherited from UnboundColumnDataEventArgs. |
| ValueType | Gets the type of data stored in the unbound column. |
Remarks
Note
The CustomUnboundColumnData event fires only for visible unbound columns.
The CustomUnboundColumnData event allows you to do the following:
- Populate cells in visible unbound columns with values.
Obtain user edits (which you can accept or discard). Read values of the
e.IsGetDataande.IsSetDataproperties to specify a different set of actions for each of these scenarios:- e.IsGetData — Returns true when the column needs to be populated and you need to provide cell values.
- e.IsSetData — Returns true when a user has changed a cell value and you need to save the modified value to a data source.
Read the following topic for additional information and examples: Unbound Columns.
Tip
Use methods provided by the bound data source to get or set cell values within the CustomUnboundColumnData event handler. The e.Row and e.ListSourceRowIndex event parameters identify the processed data row. To get values in a specific row in the data source, use the GetListSourceRowCellValue method or APIs of row objects.
Example
The following example retrieves data from a Dictionary and saves changes back to it:
// Create an unbound column that supports editing.
GridColumn unboundColumn = gridView.Columns.AddField("CustomData");
unboundColumn.UnboundDataType = typeof(string);
unboundColumn.Visible = true;
// Handle the CustomUnboundColumnData event.
Dictionary<int, string> unboundData = new Dictionary<int, string>();
unboundData[1] = "Can live up to 20 years!";
gridView.CustomUnboundColumnData += (sender, e) =>
{
if(e.Column.FieldName == "CustomData") {
// Populate columns.
if(e.IsGetData) {
if(unboundData.ContainsKey(e.ListSourceRowIndex))
e.Value = unboundData[e.ListSourceRowIndex];
}
// Post edits back to the data source.
if(e.IsSetData && e.Value != null) {
unboundData[e.ListSourceRowIndex] = e.Value.ToString();
}
}
};
Notes
- The
CustomUnboundColumnDataevent fires for each cell in visible unbound columns. TheCustomUnboundColumnDataevent may fire multiple times for each cell (due to the Grid control’s data processing algorithms). The Grid control does not cache data that you supply within theCustomUnboundColumnDataevent handler. If these data operations take too long, cache data manually. - Do not dispose of the Grid control’s data source, do not modify column settings, the grid’s layout, and the object model within the
CustomUnboundColumnDataevent handler. - Server Mode does not support data sorting, grouping, filtering, and summary calculation for unbound columns that get cell values on the
CustomUnboundColumnDataevent. These features are supported for unbound columns that are populated with unbound expressions.
Related GitHub Examples
The following code snippets (auto-collected from DevExpress Examples) contain references to the CustomUnboundColumnData event.
Note
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