带有 C# 参数的“UserControl"构造函数

本文介绍了带有 C# 参数的“UserControl"构造函数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

说我疯了，但我是那种喜欢带参数的构造函数(如果需要)的人，而不是不带参数的构造函数，然后设置属性.我的思考过程:如果实际构造对象需要属性，它们应该放在构造函数中.我有两个好处:

Call me crazy, but I'm the type of guy that likes constructors with parameters (if needed), as opposed to a constructor with no parameters followed by setting properties. My thought process: if the properties are required to actually construct the object, they should go in the constructor. I get two advantages:

我知道当一个对象被构造时(没有错误/异常)，我的对象是好的.
这有助于避免忘记设置某个属性.

在表单/用户控件开发方面，这种心态开始伤害我.想象一下这个UserControl:


This mindset is starting to hurt me in regards to form/usercontrol development. Imagine this UserControl:
public partial class MyUserControl : UserControl
{
  public MyUserControl(int parm1, string parm2)
  {
    // We'll do something with the parms, I promise
    InitializeComponent();
  }
}

在设计时，如果我将此 UserControl 放在表单上，我会得到 Exception:
At designtime, if I drop this UserControl on a form, I get an Exception:
未能创建组件MyUserControl"...
System.MissingMethodException - 没有为此对象定义无参数构造函数.

  Failed to create component 'MyUserControl' ...

      System.MissingMethodException - No parameterless constructor defined for this object.
在我看来，唯一的解决方法是添加默认构造函数(除非其他人知道方法).
It seems like, to me, the only way around that was to add the default constructor (unless someone else knows a way).
public partial class MyUserControl : UserControl
{
  public MyUserControl()
  {
    InitializeComponent();
  }

  public MyUserControl(int parm1, string parm2)
  {
    // We'll do something with the parms, I promise
    InitializeComponent();
  }
}

不包括无参数构造函数的全部意义在于避免使用它.而且我什至不能使用 DesignMode 属性来做类似的事情:
The whole point of not including the parameterless constructor was to avoid using it. And I can't even use the DesignMode property to do something like:
public partial class MyUserControl : UserControl
{
  public MyUserControl()
  {
    if (this.DesignMode)
    {
      InitializeComponent();
      return;
    }

    throw new Exception("Use constructor with parameters");
  }
}

这也不起作用:
if (LicenseManager.UsageMode == LicenseUsageMode.Designtime)

好吧，继续……
我有我的无参数构造函数，我可以把它放在表单上，表单的 InitializeComponent 将如下所示:
I have my parameterless constructor, I can drop it on the form, and the form's InitializeComponent will look like this:
private void InitializeComponent()
{
  this.myControl1 = new MyControl();

  // blah, blah
}

相信我，因为我做到了(是的，忽略了 Visual Studio 生成的评论)，我试着搞砸了，我将参数传递给 InitializeComponent 以便我可以将它们传递给 InitializeComponent 的构造函数代码>MyControl.

And trust me, because I did it (yes, ignoring the comments Visual Studio generated), I tried messing around and I passed parameters to InitializeComponent so that I could pass them to the constructor of MyControl.

这导致我这样做:

public MyForm()
{
  InitializeComponent(); // Constructed once with no parameters

  // Constructed a second time, what I really want
  this.myControl1 = new MyControl(anInt, aString);  
}

为了让我使用带有参数的 UserControl 构造函数，我必须添加第二个我不需要的构造函数吗?并实例化控件两次?

For me to use a UserControl with parameters to the constructor, I have to add a second constructor that I don't need? And instantiate the control twice?

我觉得我一定做错了什么.想法?意见?保证(希望如此)?

I feel like I must be doing something wrong. Thoughts? Opinions? Assurance (hopefully)?

带有 C# 参数的“UserControl"构造函数

问题描述

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