How To: Remove Add Button from a Grid

You can override GetButtons() method in MyGrid.cs (which is under MyProject.Script).

This removes all buttons (including refresh):

public class MyGrid : EntityGrid<MyRow>
{
    //...

    protected override List<ToolButton> GetButtons()
    {
        return new List<ToolButton>();
    }
}

To remove add button with its index (0 - first button):

public class MyGrid : EntityGrid<MyRow>
{
    //...

    protected override List<ToolButton> GetButtons()
    {
        var buttons = base.GetButtons();
        buttons.RemoveAt(0);
        return buttons;
    }
}

Working with hard coded indexes is a bad code smell

Or return a new list with your button list:

public class MyGrid : EntityGrid<MyRow>
{
    //...

    protected override List<ToolButton> GetButtons()
    {
        var buttons = new List<ToolButton>();

        buttons.Add(new ToolButton
        {
            Title = "My New Button",
            CssClass = "my-new-button",
            OnClick = delegate {
                // ...
            }
        });

        buttons.Add(NewRefreshButton(noText: true));

        return buttons;
    }
}