Code Snippet
RowDefinition rowDef = new RowDefinition();
rowDef.Height = new GridLength(100);
grid.RowDefinitions.Add(rowDef);
rowDef = new RowDefinition();
rowDef.Height = new GridLength(2, GridUnitType.Star);
grid.RowDefinitions.Add(rowDef);
rowDef = new RowDefinition();
rowDef.Height = GridLength.Auto;
grid.RowDefinitions.Add(rowDef);