Resize DataGridView At Runtime

I need my DataGridView to resize when the form is maximized and minimized.

I have tried the following:

DGVItem = new System.Drawing.Size(this.Parent.Width - 20, this.Parent.Height - 50);

I have also tried:

DGVItem.Height = this.Parent.Heigth - 50;
DGVItem.Width = this.Parent.Width - 20;

Neither of these methods work.

Any help would be appreciated.

EDIT

I have now also tried the anchor properties as follows:

DGVItem.Anchor = (AnchorStyles.Bottom | AnchorStyles.Left | AnchorStyles.Right);

Does not work at runtime.