The DblClick event is fired when user double clicks the control. Use the ItemFromPoint method to determine the cell over the cursor. Use the ExpandOnDblClk property to specify whether an item is expanded or collapsed when user double clicks it. Use the ColumnFromPoint property to get the column from point.

The following VB sample displays a message when the user double clicks an item:

Private Sub Grid1_DblClick(Shift As Integer, X As Single, Y As Single)
    With Grid1
        ' Converts the container coordinates to client coordinates
        X = X / Screen.TwipsPerPixelX
        Y = Y / Screen.TwipsPerPixelY
        Dim h As HITEM
        Dim c As Long, hit As Long
        ' Gets the item from (X,Y)
        h = .ItemFromPoint(X, Y, c, hit)
        If Not (h = 0) Or Not (c = 0) Then
            MsgBox "The '" & .Items.CellValue(h, c) & "' item has been double clicked."
        End If
    End With
End Sub

The following VB sample use DblClick event to start editing control, if the AutoEdit property is False.

Private Sub Grid1_DblClick(Shift As Integer, X As Single, Y As Single)
    ' Starts the editing operation if the user dbl click in the control
    With Grid1
        If (Not .AutoEdit) Then
            ' Did user dbl click on an item?
            Dim c As Long, hit as Long
            If Not (.ItemFromPoint(X / Screen.TwipsPerPixelX, Y / Screen.TwipsPerPixelY, c, hit) = 0) Then
                .Edit
            End If
        End If
    End With
End Sub

The following C++ sample displays the value of the cell being double clicked ( including the inner cells ):

#include "Items.h"
void OnDblClickGrid1(short Shift, long X, long Y) 
{
	long c = NULL, hit = NULL;
	long h = m_grid.GetItemFromPoint( X, Y, &c, &hit );
	if ( ( h != 0 ) || ( c != 0 ) )
	{
		COleVariant vtItem( h ), vtColumn( c );
		CString strCaption = V2S( &m_grid.GetItems().GetCellValue( vtItem, vtColumn ) );
		MessageBox( strCaption );
	}
}

where the V2S function converts a VARIANT value to a string, and may look like follows:

static CString V2S( VARIANT* pv, LPCTSTR szDefault = _T("") )
{
	if ( pv )
	{
		if ( pv->vt == VT_ERROR )
			return szDefault;

		COleVariant vt;
		vt.ChangeType( VT_BSTR, pv );
		return V_BSTR( &vt );
	}
	return szDefault;
}

The following VB.NET sample displays the value of the cell being double clicked ( including the inner cells ):

Private Sub AxGrid1_DblClick(ByVal sender As Object, ByVal e As AxEXGRIDLib._IGridEvents_DblClickEvent) Handles AxGrid1.DblClick
    Dim h As Integer, c As Integer, hit As EXGRIDLib.HitTestInfoEnum
    With AxGrid1
        h = .get_ItemFromPoint(e.x, e.y, c, hit)
        If Not (h = 0) Or Not (c = 0) Then
            MessageBox.Show(.Items.CellCaption(h, c))
        End If
    End With
End Sub

The following C# sample displays the value of the cell being double clicked ( including the inner cells ):

private void axGrid1_DblClick(object sender, AxEXGRIDLib._IGridEvents_DblClickEvent e)
{
	EXGRIDLib.HitTestInfoEnum hit;
	int c = 0, h = axGrid1.get_ItemFromPoint(e.x, e.y, out c, out hit);
	if ((h != 0) || (c != 0))
		MessageBox.Show(axGrid1.Items.get_CellCaption(h, c).ToString());
}

The following VFP sample displays the value of the cell being double clicked:

*** ActiveX Control Event ***
LPARAMETERS shift, x, y

local c, hit
c = 0
hit = 0

with thisform.Grid1
	.Items.DefaultItem = .ItemFromPoint( x, y, @c, @hit )
	if ( .Items.DefaultItem != 0 )
		wait window nowait .Items.CellCaption( 0, c )
	endif
endwith