Please refer to MSDN's TCITEM. In order to ensure the optimal size within the library when obtaining strings, does not use cchTextMax. public TCIF mask { get; set; } public TCIS dwState { get; set; } public TCIS dwStateMask { get; set; } public string pszText { get; set; } public int iImage { get; set; } public IntPtr lParam { get; set; } JR |