微软.net精简框架常见问题及回答(中文版)(47)
1.42. How can I force Visual Studio .NET 2003 to connect to newer versions of the Pocket PC 2003 emulator?
Download the Emulator ActiveSync Connection Tool from Windows Mobile Developer Power Toys:
This allows ActiveSync to connect to your Emulator session from Visual Studio .NET 2003. Create an ActiveSync session to the 4.2 emulator, this will allow Visual Studio 2003 to consider it a real device (Choose PPC device as the deployment target).
1.43. Why don't my custom controls show up properly in the toolbox?
While adding designer support in Visual Studio .NET 2003 for Smart Device custom controls, you may run into the following issues:
Unable to associate an Icon to the Control for showing it in the toolbox at design time
The component, when added to the toolbox, becomes greyed out Causes
Using a design project separate from the control project. Visual Studio .NET automatically prepends the project default namespace to the bitmap name. The "default namespace" defaults to the project name. This may be a problem because the design project has a slightly different name than the runtime project.
Not setting the correct ToolBoxItemFilterAttribute values Resolutions
Given the following example:
Runtime VS.NET Project: MyProject
Class Name: MyProject.MyClass
Design VS.NET Project Name: MyProject.Design
BitMap name in VS.NET Design Project: Foo.bmp
Bitmap name in design assembly: MyProject.Design.MyClass.bmp
-- This creates a problem because the bitmap needs the name: MyProject.MyClass.bmp
In the above example, setting the design project's default namespace to "MyProject" rather then "MyProject.Design" should fix the problem.
The easiest way to check the name of the bitmap within the assembly is to run ILDASM and open the Manifest. The embedded resources are listed at the end of the manifest.
If you create a custom component derived from the Component class, your code must include the following statements so that your component appears in the Toolbox: ToolBoxItemFilterAttribute("NETCF",ToolBoxItemFilterType.Require)
ToolBoxItemFilterAttribute("System.CF.Windows.Forms", ToolBoxITemFilterType.Custom)
2. 图形
2.1. 怎样建立一个图形对象？
有很多种方法可以建立图形对象，看你怎么用：
在OnPaint中，使用object参数提供的PaintEventArgs参数：
//C#
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.DrawLine(...);
}
'VB
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
e.Graphics.DrawLine(...)
End Sub 'OnPaint
在程序的其他部分，利用控件的一个方法，可以用来建立任意控件的图形对象：
//C#
using System.Drawing;
Graphics g = this.CreateGraphics();
'VB
Imports System.Drawing
Dim g As Graphics = Me.CreateGraphics()
直接画到bitmap位图文件中：
//C#
using System.Drawing;
Bitmap bm = new Bitmap(10,10);
Graphics g = Graphics.FromImage(bm);
'VB
Imports System.Drawing
Dim bm As New Bitmap(10, 10)
Dim g As Graphics = Graphics.FromImage(bm)
2.2. 怎样优化GDI+？
以下编码方式有助提高使用Graphics的绘图速度：
只建立一个图形对象 (或只使用OnPaint中的 PaintEventArgs)。
把所有绘图工作先画到不显示的位图上，再一次性把位图显示出来。
只重画变化的部分图象。
尽可能在相同的区域上画相同大小的图象。 主要思路：最小化地重画图象。例如，当光标拖过图象时，不需要把整个图重新画一遍。只需要重画光标之前经过的地方。
2.3. 怎样在窗体上画一个图案？
这里有个例子，告诉你怎样把图片画到窗体的背景上：
http://samples.gotdotnet.com/quickstart/CompactFramework/doc/bkgndimage.aspx