[英]How to add a border to a custom control in the design view?
透明圖像在Windows窗體中是純粹的邪惡,這就是為什么我創建了一個自定義控件類來處理它們。 設計師在空的時候不顯示我的控制權。 我想添加一個微妙的邊框,但只在設計視圖中(當用戶沒有添加邊框時)。 我該怎么做?
我的班級是:
class TransparentImage : Control
{
public Image Image { get; set; }
protected Graphics graphics;
public string FilePath { get; set; }
protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT
return cp;
}
}
protected override void OnPaintBackground(PaintEventArgs pevent)
{
// Don't paint background
}
protected override void OnPaint(PaintEventArgs e)
{
// Update the private member so we can use it in the OnDraw method
this.graphics = e.Graphics;
// Set the best settings possible (quality-wise)
this.graphics.TextRenderingHint =
System.Drawing.Text.TextRenderingHint.AntiAlias;
this.graphics.InterpolationMode =
System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
this.graphics.PixelOffsetMode =
System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
this.graphics.SmoothingMode =
System.Drawing.Drawing2D.SmoothingMode.HighQuality;
if (Image != null)
{
// Sets the images' sizes and positions
var width = Image.Size.Width;
var height = Image.Size.Height;
var size = new Rectangle(0, 0, width, height);
// Draws the two images
this.graphics.DrawImage(Image, size);
}
}
}
檢查OnPaint
if (this.DesignMode)
並調用DrawRectangle
。
您可能想要使用new Pen(SystemColors.ActiveBorder) { DashStyle = DashStyle.Dot }
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