Grouping Controls

问题:

I'm using C++ Builder 5. Is there a way to group a disparate set of controls so that by simply calling, for instance, myGroup.Enabled = false; will set all group of controls enabled property to false? I can't use a GroupBox since the controls (labels, checkboxes, etc) are on different TabPages.

The reason I ask is so I don't have to call each control's enabled property explicitly and can do it with one simple call.

If not, how can I create a custom Control class to do this?

回答1:

You could use the Tag property of the controls and create your own grouping.

void TForm1::SetControlState(TWinControl *WinCtrl, const bool IsEnabled, const int TagValue)
{
 // set the enabled property for each control with matching TagValue
 for (int Index = 0; Index < WinCtrl->ControlCount; ++Index)
 {
   if (WinCtrl->Controls[Index]->Tag == TagValue)
   {
     WinCtrl->Controls[Index]->Enabled = IsEnabled;
   }

   // set child controls
   if (WinCtrl->Controls[Index]->InheritsFrom(__classid(TWinControl)))
   {
     TWinControl *TempWinCtrl;
     TempWinCtrl = static_cast<TWinControl *>(WinCtrl->Controls[Index]);
     SetControlState(TempWinCtrl, IsEnabled, TagValue);
   }
 } // end for
}

Alternatively, If you want to enable/disable all controls in one go.

void TForm1::SetControlState(TWinControl *WinCtrl, const bool IsEnabled)
{
 // set the enabled property for each control with parent TabSheet
 for (int Index = 0; Index < WinCtrl->ControlCount; ++Index)
 {
   WinCtrl->Controls[Index]->Enabled = IsEnabled;

   // disable child controls
   if (WinCtrl->Controls[Index]->InheritsFrom(__classid(TWinControl)))
   {
     TWinControl *TempWinCtrl;
     TempWinCtrl = static_cast<TWinControl *>(WinCtrl->Controls[Index]);
     SetControlState(TempWinCtrl, IsEnabled);
   }
 } // end for
} 

Examples:

// disable all controls on the form
SetControlState(Form1, false);

// disable all controls on a tabsheet
SetControlState(TabSheet1, false);

NOTE: The above code has been tested with C++Builder 2007

回答2:

Since the controls you want to group are not in the same container, then I suggest using a TAction (look at the TActionList component). All TControl descendants have a public (sometimes even published) Action property. You can have the same TAction object assigned to multiple controls at the same time. Enabling/disabling the TAction (or updating any of its other properties) will automatically update all associated controls accordingly.