正确确定自定义绘制的复选框状态

Question

简介及相关信息:

我需要有主题的公共控件，但具有不同的文本颜色，和透明的背景。我遇到了一个问题，在这个问题中有很好的记录。

我通过处理NM_CUSTOMDRAW取得了一些进展，并决定先完成复选框。

问题:

我被困在确定复选框的状态，所以我不能传递DrawThemeBackground()的正确参数。

代码不仅仅是文字，下面是代码片段:

case WM_NOTIFY:
    {
        if( ((LPNMHDR)lParam)->code == NM_CUSTOMDRAW )
        {
            switch( ((LPNMHDR)lParam)->idFrom ) 
            {
            case IDC_CHECK1:
                {
                    switch( ((LPNMCUSTOMDRAW)lParam)->dwDrawStage  )
                    {
                    case CDDS_PREERASE:
                        {
                            HRESULT hr = DrawThemeParentBackground(
                                ((LPNMCUSTOMDRAW)lParam)->hdr.hwndFrom
                                ((LPNMCUSTOMDRAW)lParam)->hdc,
                                &((LPNMCUSTOMDRAW)lParam)->rc );
                            if( FAILED(hr) ) // if failed draw without theme
                            {
                                SetWindowLongPtr( hDlg, DWLP_MSGRESULT
                                    (LONG_PTR)CDRF_DODEFAULT );
                                return TRUE;
                            }
                            HTHEME hTheme = OpenThemeData(
                                ((LPNMCUSTOMDRAW)lParam)->hdr.hwndFrom,
                                L"BUTTON" );
                            if( ! hTheme )  // if failed draw without theme
                            {
                                CloseThemeData(hTheme);
                                SetWindowLongPtr( hDlg, DWLP_MSGRESULT
                                    (LONG_PTR)CDRF_DODEFAULT );
                                return TRUE;
                            }
                            // draw the state-->this is the problem part
                            // I thought this might be useful           
                            LRESULT state = SendMessage(
                                ((LPNMCUSTOMDRAW)lParam)->hdr.hwndFrom,
                                BM_GETSTATE, 0, 0 );
                            int stateID;  // parameter for DrawThemeBackground
                            switch( ((LPNMCUSTOMDRAW)lParam)->uItemState )
                            {
                            case CDIS_HOT:
                                {
                                    if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
                                        stateID = CBS_CHECKEDHOT;
                                    else
                                        stateID = CBS_UNCHECKEDHOT;
                                    break;
                                }
                            case CDIS_DEFAULT:
                                {
                                    if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
                                        stateID = CBS_CHECKEDNORMAL;
                                    else
                                        stateID = CBS_UNCHECKEDNORMAL;
                                    break;
                                }
                            case CDIS_FOCUS:
                                {
                                    if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
                                        stateID = CBS_CHECKEDNORMAL;
                                    else
                                        stateID = CBS_UNCHECKEDNORMAL;
                                    break;
                                }
                            case CDIS_SELECTED:
                                {
                                    if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
                                        stateID = CBS_CHECKEDPRESSED;
                                    else
                                        stateID = CBS_UNCHECKEDPRESSED;
                                    break;
                                }
                            }
                            RECT r;
                            SIZE s;
                            // get check box dimensions so we can calculate 
                            // rectangle dimensions for text
                            GetThemePartSize( hTheme, 
                                ((LPNMCUSTOMDRAW)lParam)->hdc, 
                                BP_CHECKBOX, stateID, NULL, 
                                TS_TRUE ,&s );
                            r.left = ((LPNMCUSTOMDRAW)lParam)->rc.left;
                            r.top = ((LPNMCUSTOMDRAW)lParam)->rc.top;
                            r.right = ((LPNMCUSTOMDRAW)lParam)->rc.left + s.cx;
                            r.bottom = ((LPNMCUSTOMDRAW)lParam)->rc.top + s.cy;
                            DrawThemeBackground( hTheme, ((LPNMCUSTOMDRAW)lParam)->hdc,
                                BP_CHECKBOX, stateID, &r, NULL );
                            // adjust rectangle for text drawing
                            ((LPNMCUSTOMDRAW)lParam)->rc.left +=  2 + s.cx;
                            DrawText( ((LPNMCUSTOMDRAW)lParam)->hdc,
                                L"Example text", -1, 
                                &((LPNMCUSTOMDRAW)lParam)->rc,
                                DT_SINGLELINE | DT_VCENTER );
                            CloseThemeData(hTheme);
                            SetWindowLongPtr( hDlg, DWLP_MSGRESULT
                                (LONG_PTR)CDRF_SKIPDEFAULT );
                            return TRUE;
                        }
                    }
                }
            }
        }
    }
    break;

文本颜色和文本背景在WM_CTLCOLORSTATIC处理程序中设置:

case WM_CTLCOLORSTATIC:
    {
        SetTextColor( (HDC)wParam, RGB( 255, 0, 0 ) );
        SetBkMode( (HDC)wParam, TRANSPARENT );
    }
    return (INT_PTR)( (HBRUSH)GetStockObject(NULL_BRUSH) );

我包含了#pragma comment和InitCommonControlsEx()的通用控件6。

问题:

我现在所需要的就是为DrawThemeBackground传递适当的状态。有人能帮我一下吗?

谢谢。

问好。

Answer 1

NM_CUSTOMDRAW给出了正在绘制的控件的状态信息。NMCUSTOMDRAW::uItemState字段是一个位掩码，它可以一次保存多个值，但是您没有考虑到这一点。您需要使用&位运算符来检查是否存在特定的值。

改变:

// I thought this might be useful           
LRESULT state = SendMessage(
    ((LPNMCUSTOMDRAW)lParam)->hdr.hwndFrom,
    BM_GETSTATE, 0, 0 );
int stateID;  // parameter for DrawThemeBackground
switch( ((LPNMCUSTOMDRAW)lParam)->uItemState )
{
    case CDIS_HOT:
    {
        if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
            stateID = CBS_CHECKEDHOT;
        else
            stateID = CBS_UNCHECKEDHOT;
        break;
    }
    case CDIS_DEFAULT:
    {
        if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
            stateID = CBS_CHECKEDNORMAL;
        else
            stateID = CBS_UNCHECKEDNORMAL;
        break;
    }
    case CDIS_FOCUS:
    {
        if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
            stateID = CBS_CHECKEDNORMAL;
        else
            stateID = CBS_UNCHECKEDNORMAL;
        break;
    }
    case CDIS_SELECTED:
    {
        if( IsDlgButtonChecked( hDlg, ((LPNMCUSTOMDRAW)lParam)->hdr.idFrom ) )
            stateID = CBS_CHECKEDPRESSED;
        else
            stateID = CBS_UNCHECKEDPRESSED;
        break;
    }
}

变成这样:

int stateID;  // parameter for DrawThemeBackground
UINT uiItemState = ((LPNMCUSTOMDRAW)lParam)->uItemState;
bool bChecked = (uiItemState & CDIS_CHECKED);
if (uiItemState & CDIS_HOT)
    stateID = bChecked ? CBS_CHECKEDHOT : CBS_UNCHECKEDHOT;
else if (uiItemState & CDIS_SELECTED)
    stateID = bChecked ? CBS_CHECKEDPRESSED : CBS_UNCHECKEDPRESSED;
else
    stateID = bChecked ? CBS_CHECKEDNORMAL : CBS_UNCHECKEDNORMAL;