Disable Auto-Select of DataGridView

I have a datagridview binded to a datasource.
Now, once the datasource receive data, the datagridview shows them and auto-select the first row of data(I set it to Full-Row Selection).

I want to disable this feature. ClearSelection() doesn't help in my situation. Because in my applicaiont the event"SelectionChanged" of the datagridview will trigger some actions and I don't want to perform these actions unless the user click onand select the datagridview himself.

I am using VS2005.
Could anyone help? THANKS!