DataGridViewEx.md

DataGridViewEx: Enhancing Windows Forms DataGridView

Introduction

The DataGridViewEx class is an extension class for the Windows Forms DataGridView control. It adds several useful features that make data editing more efficient and user-friendly. This article explains the main features of DataGridViewEx and provides usage examples.

Why extension class? Implementation with extensions methods required minimum changes to project to enable / disable the advance features during development. Besides, this give developers more rooms to use DataGridViewEx on 3rd party enhanced grid object derrived from DataGridView.

To activate extended features for a DataGridView object, call the EnableAdvanceControl method or any other public method in the DataGridViewEx class.

DataGridView myDataGridView = new DataGridView();
myDataGridView.EnableAdvanceControl();

Alternatively, create DataGridVewExtended object directly from Visual Studio Toolbox.

Key Features

1. Change Tracking

DataGridViewEx keeps track of modifications made to cells in the DataGridView.

• You can easily see which cells have been changed.
• Changes can be committed or reverted as needed.

After making changes to the grid:

// Check if there are uncommitted changes
if (myDataGridView.HasChanges())
{
    //Query modified cells, review changes.
    DataGridViewCell[] cellsChanged = myDataGridView.ModifiedCells();

    // Commit all changes
    myDataGridView.CommitChanges();

    // Or revert all changes
    myDataGridView.RevertChanges();
}

Modified cells are highlighted with a different background colour (default is light yellow). You can also change the default colour used to highlight modified cells:

Color currentColor = myDataGridView.GetModifiedCellColor();
myDataGridView.SetModifiedCellColor(Color.LightBlue);

2. Smart Editing

The class adds several keyboard shortcuts to speed up data entry:

• Ctrl+D: Copy values down in selected cells
• Ctrl+R: Copy values right in selected cells
• Ctrl+V: Enhanced paste from clipboard
• Delete: Clears content of selected cells (without deleting the entire row)

3. Enhanced Clipboard Operations

The paste function in DataGridViewEx is significantly improved to handle multi-cell clipboard content more efficiently. It can intelligently paste single values across multiple selected cells or distribute multi-cell content starting from the top-left of the selection. The function respects the DataGridView boundaries, handles different data types appropriately (including boolean values for checkbox columns), and maintains the structure of copied data.

To receive notifications when a value is pasted into a cell, manage event subscriptions using CellValueChangingEventAdd and CellValueChangingEventRemove for the CellValueChanging event which triggered when cell value is about to change by paste and delete operation.

The EndEdit event isn't suitable in this scenario because it requires the cell to first enter edit mode before it can be triggered.

private void DgvEnable_Click(object sender, EventArgs e)
{
    Dgv.EnableAdvanceControl();
    Dgv.CellValueChangingEventAdd(valueChanging);
}

private void valueChanging(object sender, DataGridViewCellEventArgs e)
{
    Trace.WriteLine($"Value updating at cell {e.RowIndex}, {e.ColumnIndex} = {e.NewValue.ToString()}");
    
    //Option: Review new value and update if necessary.
    if(e.NewValue ... ) e.NewValue = ... ;
    
    //Option: Cancel update for this cell when necessary
    e.Cancel = true;   
}

Benefits

1. Improved User Experience: Users can easily see which cells they've modified.
2. Error Prevention: The ability to revert changes helps prevent accidental data modifications.
3. Efficient Editing: Keyboard shortcuts and smart pasting make data entry faster.
4. Better Control: Developers have more control over the editing process and can manage changes programmatically.

Conclusion

DataGridViewEx significantly enhances the standard DataGridView control. It's particularly useful for applications that involve frequent data editing, where tracking and managing changes is important. By using this extension, you can create more robust and user-friendly data editing interfaces in your Windows Forms applications.