BCB DBGrid滑轮滚动

BCB的DBGrid不支持鼠标滑轮滚动,只能点击ScrollBar的上下键移动,很不方便,下面使用替换窗口过程模拟上下键点击来支持滑轮滚动

代码编写者:妖哥

FARPROC pOldProc = NULL; // 用于保存DBGrid控件旧的WindowProc
//---------------------------------------------------------------------------
// DBGrid新的WindowProc
LRESULT CALLBACK DBGridProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    // 处理感兴趣的Window消息
    if (uMsg == WM_MOUSEWHEEL)
    {
        if ((short)HIWORD(wParam) > 0)
        {
            ::PostMessage(hWnd, WM_VSCROLL, SB_LINEUP, 0);
        }
        else
        {
            ::PostMessage(hWnd, WM_VSCROLL, SB_LINEDOWN, 0);
        }
    }
    // 调用原DBGrid的WindowProc
    return (::CallWindowProc(pOldProc, hWnd, uMsg, wParam, lParam));
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::FormShow(TObject *Sender)
{
    // 设置新的窗体函数
    pOldProc = (FARPROC)::SetWindowLong(DBGrid->Handle, GWL_WNDPROC, (long)DBGridProc);
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::FormClose(TObject *Sender, TCloseAction &Action)
{
    // 还原窗体函数
    ::SetWindowLong(this->DBGrid->Handle, GWL_WNDPROC, (long)pOldProc);
}

本人封装的类:

#ifndef REPLACEPROC_H
#define REPLACEPROC_H

#include <windows.h>
#include <map>
using namespace std;

class ReplaceDBGridWndProc
{
    static map<HWND,WNDPROC> s_MapofOldProc;
    static WNDPROC s_OldWndProc;
    static LRESULT CALLBACK NewWndProc(HWND hwnd,UINT message,WPARAM wParam,LPARAM lParam)
    {
        if (message == WM_MOUSEWHEEL)  
        {  
            if ((short)HIWORD(wParam) > 0)  
            {  
                ::PostMessage(hwnd, WM_VSCROLL, SB_LINEUP, 0);  
            }  
            else  
            {  
                ::PostMessage(hwnd, WM_VSCROLL, SB_LINEDOWN, 0);  
            }  
        }  
        map<HWND,WNDPROC>::iterator it=s_MapofOldProc.find(hwnd);
        LRESULT result;
        if(it!=s_MapofOldProc.end())
        result=CallWindowProc(it->second,hwnd,message,wParam,lParam);
        else
        result=DefWindowProc(hwnd,message,wParam,lParam);
        return result;   
    }
public:
    static void ReplaceWndProc(HWND hwnd)
    {
        s_MapofOldProc[hwnd]=(WNDPROC)SetWindowLong(hwnd,GWL_WNDPROC,(LONG)NewWndProc);
    }

};
WNDPROC ReplaceDBGridWndProc::s_OldWndProc=NULL;
map<HWND,WNDPROC> ReplaceDBGridWndProc::s_MapofOldProc;
extern ReplaceDBGridWndProc g_ReplaceProc;
#endif





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