title: DataGridViewTextBoxColumn that changes to ComboBox on editing
body: <p>I want to show a DataGridView with a ComboBox column that looks like a DataGridViewTextBoxColumn. </p>
  
  <p>In DataGridView I have the DataGridViewTextBoxColumn displayed and when the user sets Focus on a cell in this column, the cell should be changed to ComboBox. </p>
  
  <p>I don't know which function has to be overriden. </p>
  
  <p>In DataGridTextBoxColumn there is the function Edit, can I can draw my combobox during this function?</p>