I was wondering if anyone knew of a way to do multi-row selections in a data
grid with a simple mouse click without using the shift key or the row
headers.  Simply  we want our users to be able to select several rows by
clicking on them with their mouse and have them all remain highlighted.  We
also would like to do the inverse and allow them to click on a highlighted
row and that row would then become unselected.

We have attempted to do this by inheritting the .NET datagrid and
implementing the functions below but this does not seem to work.  Any help
would be appreciated.

The version of .NET we are using is 1.1.

public const int  gintNO_SELECTION = -1;

           protected bool mblnFullRowSelect = true;

           protected System.Windows.Forms.DataGridTableStyle gtsTableStyle;

           protected int mintCurrentDataGridRowIndex = 0;        // Used by
certain derived forms for keeping track of current data grid row edits.

           private ArrayList maintSelectedIndexes = new ArrayList();

           private bool mblnMultiSelect = true;            

           

public new void Select(int vintIndex)

           {

                 int lintIndex = 0;

                 BaseTraceManagement.LogFunctionEntry(TraceLevel.Info);

                 try

                 {

                       // If we don't allow multi select then unselect the
current row first.

                       if(!mblnMultiSelect)

                       {

                             UnSelect(mintCurrentDataGridRowIndex);

                       }

                       // Only continue if we are doing full row selection.

                       if(!mblnFullRowSelect)

                       {

                             return;

                       }

                       // Loop through our array list of indexes and check
to see if the row is already selected.

                       // NOTE: Can't use IsSelected() as it always returns
false.

                       for(lintIndex = 0; lintIndex <
maintSelectedIndexes.Count; ++lintIndex)

                       {

                             // If we have a match then unselect the row
and return.

                             if(vintIndex ==
Convert.ToInt32(maintSelectedIndexes[lintIndex]))

                             {

                                   UnSelect(vintIndex);

                                   return;

                             }

                       }

                       // Select the row.

                       base.Select(vintIndex);

                       // Keep track of the new selection.

                       maintSelectedIndexes.Add(vintIndex);

                       // Indicate the current new row selected.

                       mintCurrentDataGridRowIndex = vintIndex;

                 }

                 finally

                 {

                       BaseTraceManagement.LogFunctionExit(TraceLevel.Info);

                 }

           }

           

           public new void UnSelect(int vintIndex)

           {

                 int lintIndex = 0;

                 BaseTraceManagement.LogFunctionEntry(TraceLevel.Info);

                 try

                 {

                       // Loop through all items being tracked and remove
the relevant one.

                       for(lintIndex = 0; lintIndex <
maintSelectedIndexes.Count - 1; ++lintIndex)

                       {

                             // If we don't allow multi-select or the row
index matches then remove the row.

                             if(!mblnMultiSelect ||
(Convert.ToInt32(maintSelectedIndexes[lintIndex]) == vintIndex))

                             {

                                   // Unselect the row.

                                   base.UnSelect(vintIndex);

                                   // Remove the selection.

                                   maintSelectedIndexes.RemoveAt(lintIndex);

                                   break;

                             }

                       }

                       // If the current row index matches the supplied
index (or we don't allow for multi-select) then reset it.

                       if(mblnMultiSelect || (mintCurrentDataGridRowIndex
== vintIndex))

                             mintCurrentDataGridRowIndex = gintNO_SELECTION;

                 }

                 finally

                 {

                       BaseTraceManagement.LogFunctionExit(TraceLevel.Info);

                 }

           }