Question

我在C＃Winform onPaint事件中绘制了一个区域。我不希望在全屏模式下进行这些更改。我试图保存并恢复图形但无法做到，如果我遗漏了某些内容，请告诉我。

//class member
bool mFullSize = false;
    GraphicsState transState;
protected override void OnPaint(PaintEventArgs e)
{

    base.OnPaint(e);

 // Save translated graphics state.


    Graphics gr = e.Graphics;
    transState = gr.Save();
    int x = 50;
    int y = 50;
    int width = 100;
    int height = 100;

    Rectangle rect = new Rectangle(x, y, width / 2, height / 2);
    Region region = new Region(rect);

    GraphicsPath path = new GraphicsPath();
    path.AddPie(x, y, width, height, 180, 90);
    region.Exclude(path);

    if (!mFullSize)
    {
        gr.FillRegion(Brushes.Black, region);
    }
    else
    {
        gr.Restore(transState);
    }

}


 protected override void OnResize(EventArgs e)
{
    if (this.WindowState == FormWindowState.Maximized)
    {
        mFullSize = true;
    }
    else
    {
        mFullSize = false;
    }

}

Answer 1

为什么不在表单完整大小时返回？无论如何它都是在最大化上绘制的，所以我认为没有必要（重新）存储任何图形状态。

protected override void OnPaint(PaintEventArgs e)
{
    base.OnPaint(e);
    if (WindowState == FormWindowState.Maximized) return; // just don't paint the things you don't want to

    Graphics gr = e.Graphics;
    int x = 50;
    int y = 50;
    int width = 100;
    int height = 100;

    Rectangle rect = new Rectangle(x, y, width / 2, height / 2);
    Region region = new Region(rect);

    GraphicsPath path = new GraphicsPath();
    path.AddPie(x, y, width, height, 180, 90);
    region.Exclude(path);

    gr.FillRegion(Brushes.Black, region);
}

更新：最大化时问题是OnResize未被调用。您需要使用OnSizeChanged或直接在WindowState方法中查看OnPaint。

UPDATE2：第一次更新不完全正确（调试消息中的错误）。 OnResize实际上是被调用的。但您忘记拨打base.OnResize，因此OnPaint未被呼叫。

因此请务必在重载中调用base.OnResize。在您的OnPaint中，您可以直接查看WindowState，如果您的表单已最大化，请避免绘画。

protected override void OnResize(EventArgs e)
{
    // DON'T FORGET TO CALL THE BASE METHOD
    base.OnResize(e);
    mFullSize = this.WindowState == FormWindowState.Maximized;
}

如何撤消Winform中OnPaint Event中所做的更改？

1 个答案: