Extension methods to save/load column settings to/from the current user registry for a DataGridView control.

SaveColumnSettings.cs

/// <summary>
/// Generate a backslash separated path showing parent\child\grandchild relationship. 
/// </summary>
public static string GeneratePath( this Control control )
{
	string path = control.Name;
	for( Control parent = control.Parent; parent != null; parent = parent.Parent)
		path = String.Format("{0}\\{1}",parent.Name,path);
	return path;
}
/// <summary>
/// Save datagridview column settings to current user registry
/// </summary>
/// <param name="gridview">DataGridView control to save settings for</param>
public static void SaveColumnSettings( this DataGridView gridview )
{
	string basePath = String.Format("Software\\{0}\\{1}\\{2}",Application.CompanyName,Application.ProductName,gridview.GeneratePath());
	foreach( DataGridViewColumn column in gridview.Columns )
	{
		string path = String.Format("{0}\\{1}",basePath,column.Name);
		using( Microsoft.Win32.RegistryKey key = Microsoft.Win32.Registry.CurrentUser.CreateSubKey(path) )
		{
			key.SetValue("Width",column.Width,Microsoft.Win32.RegistryValueKind.DWord);
			key.SetValue("DisplayIndex",column.DisplayIndex,Microsoft.Win32.RegistryValueKind.DWord);
		}
	}
}
/// <summary>
/// Read column settings from registry. 
/// </summary>
/// <param name="gridview">DataGridView control to load settings for</param>
public static void LoadColumnSettings( this DataGridView gridview )
{
	string basePath = String.Format("Software\\{0}\\{1}\\{2}",Application.CompanyName,Application.ProductName,gridview.GeneratePath());
	foreach( DataGridViewColumn column in gridview.Columns )
	{
		string path = String.Format("{0}\\{1}",basePath,column.Name);
		using( Microsoft.Win32.RegistryKey key = Microsoft.Win32.Registry.CurrentUser.CreateSubKey(path) )
		{
			//int preferredWidth = column.GetPreferredWidth(column.AutoSizeMode,true);
			column.Width = (int)key.GetValue("Width",column.Width);
			column.DisplayIndex = (int)key.GetValue("DisplayIndex",column.DisplayIndex);
		}
	}
}