<div>
If all three doc classes have the same base class then you can just use doc.Activate() without any casting.
</div>

<div>
Each doc class represents a different WinForm being loaded as an MDI child form. 
 
It's possible that the base class for all three different types of child form all natively support &quot;activate()&quot;, but what if I want to call a user function within the object? 
 
For instance, in another spot in my app, I would need to call something like this: 
 

<pre><code class="code-1 nolinks" id="code-20-41379718-1">Object doc = ActiveMdiChild;
string s = doc.GetType().ToString();
((s)doc).ZoomIn();
</code></pre>
 
ZoomIn() would be a function present in each of the different child form classes; in the case of the &quot;ToursForm&quot; object type, that would just be an empty stub for compatibility, but the other two types host browser controls that implement zoomin differently, thus the need to have the functionality for zoom within the form, rather than trying to handle it correctly from the parent form. 
 
Thoughts?
</div>

<div>
I found an interesting link, which seems to describe what I want to do, ie, dynamically cast the object to the right type so that I can access its' methods: 
 
<a href="http://stackoverflow.com/questions/4925718/c-dynamic-runtime-cast" rel="ugc">http://stackoverflow.com/questions/4925718/c-dynamic-runtime-cast</a>&nbsp; 
 
A function proposed in that solution goes like this: 
 

<pre><code class="code-1 nolinks" id="code-20-41379729-1">public static dynamic Cast(dynamic obj, Type castTo)
{
 return Convert.ChangeType(obj, castTo);
}
</code></pre>
But I don't understand it well enough to be sure it does what I need.
</div>

<div>
AndyAinscow has the right idea here. You should make sure all of your MDI child forms inherit from the same base class then create virtual methods for the base class for each action that you would like the child forms to perform. Then you override those virtual methods in inherited classes where you would like custom functionality. Leverage the inheritance and polymorphism aspects of object oriented programming. I use this technique frequently. 
 
My most recent application uses it in EXACTLY this way. I have MDI child forms that all inherit from a subclass of Form. The MDIChildForm subclass has a virtual method called UpdateData(). I then override the virtual method so each of the child forms can update their data (and associated controls) appropriately.
</div>

<div>
<blockquote>
I think you would still have to use the switch to 'know' the relevant type of object.
</blockquote>
Nah. Just us is or as: 
 
e.g. 
 

<pre><code class="code-1 nolinks" id="code-20-41379829-1">BaseClass instance = ActiveMdiChild as BaseClass;

if (instance != null)
{
 instance.Activate();
}
</code></pre>
</div>

<div>
Okay, so is it more like this link? <a href="http://stackoverflow.com/questions/14320952/dynamic-cast-using-type-of-object-c-sharp" rel="ugc">http://stackoverflow.com/questions/14320952/dynamic-cast-using-type-of-object-c-sharp</a>&nbsp; 
 
He describes it like this: 

<blockquote>
I have one abstract class named A, and other classes (B, C, D, E, ...) that implements A
</blockquote>
And so, in my case, I might create a class called childForm as the base class, and then each of the other actual types would inherit from that? I understand the concept, but not the syntax I'm seeing in that link.
</div>

<div>
You shouldn't need reflection at all for this task. Just use polymorphism as has been explained. You can use the as operator that I showed above if you cannot wholly rely on polymorphism.
</div>

<div>
^^ Agreed. 
 
This is exactly the sort of problem that Object Oriented design is made for. Base class, virtual method, overrides, polymorphism. 
 
<a href="http://stackoverflow.com/questions/7747934/can-someone-explain-polymorphism-to-me" rel="ugc">http://stackoverflow.com/questions/7747934/can-someone-explain-polymorphism-to-me</a>
</div>

<div>
@kaufmed 
&gt;&gt;I think you would still have to use the switch to 'know' the relevant type of object. 
&gt;&gt;&gt;&gt;Nah. Just us is or as: 
 
You'd misunderstood. &nbsp;The asker had found a helper function like ConvertInto(ob, typeCat) if one wanted a Cat or ConvertInto(ob, typeDog) in the link - it would still require a switch or similar because of the different types of object. 
 
 
 
Should the different types of doc not have a common base class you could always use an interface you designed yourself that each inherit from. &nbsp; 
All three of us seem to be in agreement - use a common base class with the specific code in the three derived classes and let the system call the correct code automatically.
</div>

<div>
Thank you very much for all your input! Creating the BaseClass is apparently what I need to do for this application! 
 
I feel like I understand the problem a little better now, but I definitely have some studying to do. 
 
If anybody has a good example for me, to work with, I'd appreciate it! 
 
Thanks again!
</div>

<div>
Hello, 
 
I've been trying to wrap my head around this, and and I just can't seem to get it without being able to see a working example. I've tried doing some googling, but not much luck. 
 
Any ideas? 
 
Thanks! 
 
--Jon
</div>

<div>
Create a new windows form project, on the form add one button. &nbsp;This will demonstrate polymorphism. 
 
 

<pre><code class="code-10 nolinks" id="code-20-41386511-1">namespace WindowsFormsApplication7
{
 public partial class Form1 : Form
 {
 public Form1()
 {
 InitializeComponent();
 }

 private void button1_Click(object sender, EventArgs e)
 {
 Cat cat = new Cat();
 Process(cat);
 Dog dog = new Dog();
 Process(dog);
 }

 private void Process(object ob)
 {
 String s;
 //s = String.Format(&quot;Passed in an object of type {0} /r/n and it is returning from WhatAmI {1}&quot;, ob.GetType(), ob.WhatAmI()); //FAILS - ob.WhatAmI doesn't compile
 Animal animal = (Animal)ob;
 s = String.Format(&quot;Passed in an object of type {0} \r\n and it is returning from WhatAmI: {1}&quot;, ob.GetType(), animal.WhatAmI()); //Note ob is casted to the base type: Animal 
 MessageBox.Show(s);
 }
 }

 public abstract class Animal
 {
 public abstract String WhatAmI();
 }

 public class Cat : Animal
 {
 public override String WhatAmI()
 {
 return &quot;I am a Cat&quot;;
 }
 }

 public class Dog : Animal
 {
 public override String WhatAmI()
 {
 return &quot;I am a Dog&quot;;
 }
 }
}
</code></pre>
</div>

<div>
<div class="content wysiwyg-content">
Hello Experts, 
 
I need help simplifying this bit of code: 
 

<pre><code class="code-10 nolinks" id="code-10-28902996-1">Object doc = ActiveMdiChild;
string s = doc.GetType().ToString();
switch (s)
{
	case &quot;KTStoreHouseCS.WebDocument&quot;:
		((WebDocument)doc).Activate();
		break;
	case &quot;KTStoreHouseCS.WebIEDocument&quot;:
		((WebIEDocument)doc).Activate();
		break;
	case &quot;KTStoreHouseCS.ToursForm&quot;:
		((ToursForm)doc).Activate();
		break;
	default:
		break;
}
</code></pre>
 
I feel like I should be able to dispose of the switch statement, and just use something like this, but I don't know how to make it work: 
 

<pre><code class="code-1 nolinks" id="code-10-28902996-2">Object doc = ActiveMdiChild;
string s = doc.GetType().ToString();
((s)doc).Activate();
</code></pre>
 
Any ideas? 
 
Thanks in advance! 
 
--Jon
</div>
</div>

Hello Experts,

I need help simplifying this bit of code:

(CODE)

I feel like I should be able to dispose of the switch statement, and just use something like this, but I don't know how to make it work:

(CODE)

Any ideas? 

Thanks in advance!

--Jon

Need help simplifying C# code

C# is an object-oriented programming language created in conjunction with Microsoft’s .NET framework. Compilation is usually done into the Microsoft Intermediate Language (MSIL), which is then JIT-compiled to native code (and cached) during execution in the Common Language Runtime (CLR).