Question

My question is very simple – after data binding I want to set all columns width so that it will not be horizontal scrolling. Something like this:

    columnWidth = grid.width/grid.Columns.Count

But this expression does not consider the "left part of gridView" with which I can select row, which displays current row. How can I calculate its width? [(grid.width – X)/grid.Columns.Count]

Answer 1

Very easy to do this. Just set the DataGridView.AutoSizeColumnMode property to Fill.

grid.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;

And you may need to explicitly ask the grid to resize column spacing. I can’t remember for sure. But that is simple to do:

grid.AutoResizeColumns();

According to the documentation, Fill will do the following:

The column widths adjust so that the widths of all columns exactly
fill the display area of the control, requiring horizontal scrolling
only to keep column widths above the DataGridViewColumn.MinimumWidth
property values. Relative column widths are determined by the relative
DataGridViewColumn.FillWeight property values.

So basically, as long as you don’t have any columns with a MinimumWidth that will prevent it, this property does exactly what you are looking for.

EDIT: Addressing the comment of the OP:

You can always create a simple property to report that information to you. Something like…

public int DataGridViewDeadSpaceWidth
{
    get
    {
        int x = grid.Width;
        foreach (DataGridViewColumn column in grid.Columns)
            x -= column.Width;

        return x;
    }
}

You could also use this to inherit from a DataGridView and add the property yourself to the control. Note that there is probably some other dead space from the borders of the DataGridView that you need to account for.