C＃winforms在运行时实例化未知（在设计时）表单（后期绑定？）

Question

I have a need to instantiate an instance of a dll containing a form at runtime. Currently I have a long switch statement with 75+ cases and growing rapidly. As this has all developed we have also developed a List that contains all the info to dynamically call the form.

Sample case now

...
case "state"
  State state = new State();
  state.Parent = this.Parent;
  state.ScreenNameLong = "State ";
  state.ScreenTitle = "St11 - State";
  state.SetupForm();
  this.OpenForm(state, state.ScreenTitle);
  break;
...

All info needed is now contained in a list element called menuItem which is already selected. It has form ("State"), ScreenNameLong, ScreenTitle etc.. All forms to be called have Parent objects and SetupForm() methods.

All dll's are referenced in "using" statements and in project references. It seems I should somehow be able to do something similar to this, once:

Form formToLaunch = (menuItem.form);
formToLaunch.Parent = this.Parent;
formToLaunch.ScreenNameLong = menuItem.descr;
formToLaunch.ScreenTitle = menuItem.scrNumber + " " + formToLaunch.ScreenNameLong;
formToLaunch.SetupForm();
this.OpenForm(formToLaunch, formToLaunch.ScreenNameLong );

I have beat my head against the wall and not found a good solution to this. I have researched using Reflection and Interfaces and they don't seem to fit the bill, or I am just not getting it...

Answer 1

All your forms will need to implement an interface defining the common members, for example:

interface IForm : IDisposable
{
    Form Parent { get; set; }
    string ScreenNameLong { get; set; }
    string ScreenTitle { get; set; }
    void SetupForm();
}

Here IForm inherits from IDisposable per dbc's comment below.

Get the Type from the typename (presumably in your menuItem.form ). You might need to play around with this:

var type = Type.GetType("form_namespace." + menuItem.form + ", form_assembly_name");

Instantiate the type, cast as your interface, and do whatever you want with it:

var formToLaunch = Activator.CreateInstance(type) as IForm;
if (formToLaunch != null)
{
    formToLaunch.Parent = this.Parent;
    formToLaunch.ScreenNameLong = menuItem.descr;
    formToLaunch.ScreenTitle = menuItem.scrNumber + " " + formToLaunch.ScreenNameLong;
    formToLaunch.SetupForm();
    this.OpenForm(formToLaunch, formToLaunch.ScreenNameLong);
}