擷取物件屬性，選取新的物件

應用程式可以藉由呼叫 getCurrentObject 和 GetObject 函式，來擷取畫筆、筆刷、調色盤、字型或位圖的屬性。 GetCurrentObject 函式會傳回句柄，識別目前選取至 DC 的物件;GetObject 函式會傳回描述物件屬性的結構。

下列範例示範應用程式如何擷取目前的筆刷屬性，並使用擷取的數據來判斷是否需要選取新的筆刷。

    HDC hdc;                     // display DC handle  
    HBRUSH hbrushNew, hbrushOld; // brush handles  
    HBRUSH hbrush;               // brush handle  
    LOGBRUSH lb;                 // logical-brush structure  
 
    // Retrieve a handle identifying the current brush.  
 
    hbrush = GetCurrentObject(hdc, OBJ_BRUSH); 
 
    // Retrieve a LOGBRUSH structure that contains the  
    // current brush attributes.  
 
    GetObject(hbrush, sizeof(LOGBRUSH), &lb); 
 
    // If the current brush is not a solid-black brush,  
    // replace it with the solid-black stock brush.  
 
    if ((lb.lbStyle != BS_SOLID) 
           || (lb.lbColor != 0x000000)) 
    { 
        hbrushNew = GetStockObject(BLACK_BRUSH); 
        hbrushOld = SelectObject(hdc, hbrushNew); 
    } 
 
    // Perform painting operations with the solid-black brush.  
 
 
    // After completing the last painting operation with the new  
    // brush, the application should select the original brush back  
    // into the device context and delete the new brush.  
    // In this example, hbrushNew contains a handle to a stock object.  
    // It is not necessary (but it is not harmful) to call  
    // DeleteObject on a stock object. If hbrushNew contained a handle  
    // to a brush created by a function such as CreateBrushIndirect,  
    // it would be necessary to call DeleteObject.  
 
    SelectObject(hdc, hbrushOld); 
    DeleteObject(hbrushNew); 

注意

應用程式第一次呼叫 selectObject 函式時，儲存了原始筆刷句柄。 儲存此句柄，以便在最後一個繪製作業完成新筆刷之後，將原始筆刷選取回 DC。 選取原始筆刷回到DC之後，就會刪除新的筆刷，釋放GDI堆積中的記憶體。