How may I get a DataGridView column of signed numeric values to sort by signed value? Currently ColumnType is DataGridViewTextBoxColumn and ValueType is typeof(System.Single), but sorting is on the absolute rather than signed value, e.g:
-2.728
3.835
4.132
-4.511
Ignore what ValueType and column type are.
What is the type of the actual objects in the cells (dataGrid[x, y].Value.GetType())? You are probably filling the grid with System.String objects. If you fill the grid with System.Single objects they will be sorted properly.
Another option is to handle the SortCompare event.