DataGridViewCell's style not updating on time

Question

I am writing a C# application (windows forms) in which I have a 10x10 DataGridView which represents a maze. When a cell is clicked, I add the corresponding x and y to a 2D array. Each cell that is clicked, should display a black background.

On CellClick:

        int row = dataGridView1.CurrentCell.RowIndex;
        int column = dataGridView1.CurrentCell.ColumnIndex;

        maze[row, column] = 1;

        dataGridView1.Refresh();

I've also implemented a handler for CellFormatting event:

if (maze[e.RowIndex,e.ColumnIndex] == 1){
       e.CellStyle.BackColor = Color.Black;
   }

Now when I click a cell, the style is not being updated. When I click another cell after that, the previous cell's style is updated. I've tried to both Refresh() and Update the control, but no luck.

How can I solve this problem, so a cell's style is immediately updated when it is clicked?

Answer 1

You can use these events to paint current cell on click or key down:

Private Sub DataGridView1_CellClick(sender As Object, e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellClick

    'put here your code to add CurrentCell to maze array

    Me.PaintCurrentCell()

End Sub

Private Sub DataGridView1_KeyDown(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles DataGridView1.KeyDown

    If e.KeyCode = Keys.Space Then Me.PaintCurrentCell()

End Sub

Private Sub DataGridView1_SelectionChanged(sender As Object, e As System.EventArgs) Handles DataGridView1.SelectionChanged

    Me.DataGridView1.CurrentCell.Style.SelectionBackColor = Me.DataGridView1.CurrentCell.Style.BackColor

End Sub

Private Sub PaintCurrentCell()

    Me.DataGridView1.CurrentCell.Style.BackColor = Color.Black
    Me.DataGridView1.CurrentCell.Style.SelectionBackColor = Color.Black

End Sub