Question

I am working on implementing the re-sizing feature in WPF DataGrid, it supports re-sizing through column/row headers but what I want is to allow re-sizing on grid lines.

So, user can re-size rows/columns from anywhere in DataGrid. I have been able to implement the functionality and it works fine for columns but in case of rows its messed up.

You can re-size a row through header and you can also re-size through any cell of that row but problem occurs if you use them together i.e once you have re sized a row through a cell, re-sizing through row header would stop working(shows weird behavior). Here is how it looks like (notice the broken grid lines…) –

I have created a sample to reproduce this behavior –

WPF Toolkit DataGrid Sample – Adding GridLines Resizing

To reproduce the problem

1. Re-size a row through grid-lines(any cell) and then

2. Re-size the same row through row header.

will appreciate any kind of help.

Thanks

Answer 1

I solved the problem by setting the height of CellPresenter instead of Row. Here is the main code block –

double newHeight = cellsPresenter.ActualHeight + e.VerticalChange;     
DataGridRowHeader rowHeader = GetFirstVisualChild<DataGridRowHeader>(row);    
if (rowHeader != null)    
{ 
    // clamp the CellsPresenter size to the MaxHeight of Row, 
    // because row wouldn't grow any larger
    double maxHeight = row.MaxHeight;
    if (newHeight > maxHeight)
    {
        newHeight = maxHeight;
    }
}

cellsPresenter.Height = newHeight;

// Updating row's height doesn't work correctly; shows weird behavior    
// row.Height = newHeight >= 0 ? newHeight : 0;

I have blogged about this in detail here –

WPF DataGrid Customization: Resizing Row/Column through DataGridCell gridlines