I have to work on a project on which there are several Form which have 80% of the code the same. So I try to create a generic class to make inheritate all my Forms of the UserControl class (the basic one) and my own class. But .Net doesn't support multi classs inheritance. So I create a middle class to do the inheritance chain like I can see on the net but I think I miss another step. Each class is in a different file for information.
The problem is I can't open anymore the designer for my initial Forms, because "Visual Studio cannot open a designer for the file because the class within it does not inherit from a class that can be visually designed".
Other information, I have a Mainwindow which inherite from "Form" and call one or another UserControl I design to show it.
What I had at the beginning :
namespace i2SIMDCProduction
{
public partial class MyForm1 : UserControl
{
public MyForm1(MyOwnClass myClass)
{
InitializeComponent();
this.myClass = myClass;
}
}
}
namespace i2SIMDCProduction
{
public partial class MyForm2 : UserControl
{
public MyForm2(MyOwnClass myClass)
{
InitializeComponent();
this.myClass = myClass;
}
}
}
What I have now :
namespace i2SIMDCProduction
{
public partial class MyForm1 : MyMiddleClass
{
public MyForm1(MyOwnClass myClass)
{
InitializeComponent();
this.myClass = myClass;
}
}
}
namespace i2SIMDCProduction
{
public partial class MyForm2 : MyMiddleClass
{
public MyForm2(MyOwnClass myClass)
{
InitializeComponent();
this.myClass = myClass;
}
}
}
namespace i2SIMDCProduction
{
public partial class MyMiddleClass : UserControl
{
public void MethodForAllChild()
{
}
}
}
Thank you in advance for any kind of help. I tried different things already (create a third class at the top of the file of my Forms for example, create empty constructor, ...) but nothing which works for now. The more frustrating is it is compiling and working but only the designer is KO.
If you want different forms to share the same visual controls on the screen then you set up inheritance between the forms.
Use the inherited form option in Visual Studio
For example, Form1 has a group box, with a label and two text boxes
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void CommonMethod()
{
}
}
and Form2 inherits from From1 and adds a list box
public partial class Form2 : Form1
{
public Form2()
{
InitializeComponent();
}
public void SpecificMethod()
{
base.CommonMethod();
}
}
As you can see the controls from Form1 show up on Form2 also with a little icon to indicate that they are inherited.
If instead you just need to share code (like business logic) and not visual controls, then you create a separate class to hold the code with a link to the parent form, and then each form should contain an instance of this class.
What you want to do is a Model-View-Controler setup, where the Model is only data-related classes, View is only UI code, and the controller goes between the two doing the heavy lifting with processing user inputs and updating values.
The inheritance and designer in Windows Forms is a problem.
I have a Form with an splitter, two listboxes and some other controls. That form is used to translate (map) some items. You select one item at left, one at right and click button to match. They are the same item in different providers.
I have another provider that require some extra controls to do the translation. May be 90% or more of the code is the same, but I need some extra for this provider.
The options that I saw:
Add these extra controls (protected or public) to the Form, hidden by default and without use. In Form derived class, you use them. You haven't the designer in derived Form, but you don't need because controls are in base Form. The problem with this approach is that the designer part of inheritance of derived Form is in base Form. It's a nonsense. I don't recomend this option.
Don't use the designer in derived Form. Starting in the previous point, copy the designer code added for your derived Form into your derived Form and leave your base Form as at first stage, without nothing of derived Form. You don't use the designer but you can use it temporary, copy/paste and have a good inheritance... without the designer in derived Form. It's a good option if your derived Forms has few changes, few maintenance in the designer part.
You can "Add" some logic to your base Form to allow extensions. For example, below of the ListBox, I can add a Panel (hidden by default) and some methods like ShowLeftPanel/ShowRightPanel. By default, these panels aren't used, but in derived class I can add an UserControl in left panel and show it. And that UserControl show the properties that I need to show in the special provider. Add some virtual methods for listbox selection changed, to update the UserControl. In this way, your UserControl has designer and also the base Form. You only need add some "extension points" in your form (a Panel, a Splitter...) and give some methods to interact with this parts of the base Form. And this is ok with inheritance because is something generic, like Tag property in controls.
UPDATE
Check this solution and tell me about it. Make your Forms like this:
public partial class MyForm1 : UserControl, IMyUserControl
{
private readonly MyOwnClass myClass;
public MyForm1(MyOwnClass myClass, MyMiddleClass myMiddle)
{
InitializeComponent();
this.myClass = myClass;
this.MyMiddle = myMiddle;
}
public MyMiddleClass MyMiddle { get; }
}
In this way, all your panel's forms are IMyUserControl:
public class MyUserControl : IMyUserControl
{
public MyMiddleClass MyMiddle { get; }
}
So, having any of your panel's form, you can cast to IMyUserControl and get the related MyMiddleClass having access to methods like MethodForAllChild:
public class MyMiddleClass
{
public void MethodForAllChild()
{
}
}
In your main form, you may have some property or method that give you access to your UserControl. Create a method that give you the middle instance of the current UserControl:
private MyMiddleClass GetMyMiddle()
{
UserControl userControl = GetYourMainFormCurrentUserControl();
IMyUserControl myUserControl = userControl as IMyUserControl;
return myUserControl?.MyMiddle;
}
And use it in your main form when you need:
MyMiddleClass myMiddle = GetMyMiddle();
if (myMiddle != null)
{
myMiddle.MethodForAllChild();
}
In this way, you only need implement the interface and add a property in your forms/usercontrols. In the main form you can get this middleclass and the code to reuse is only in that class and shared in all places. You don't need copy/paste if you add or change something in the middle class.
UPDATE 2
I'm going to explain in other form how it works because the code is written above. The goal is having the code only in one place, without duplicate it.
You define an interface in a very similar way as a class but without implementation (this is not really true in lastest C# versions but we can suppose that is without code). C# don't allow multiple inheritance but you can derive from a class and implement as many interfaces as you want.
When we define IMyUserControl we are telling that every class that implements IMyUserControl, has a property MyMiddle. When MyForm1 implements IMyUserControl, if you don't add the MyMiddle property, you get a compiler error. The key with this solution is that add and implement this interface in each form is very easy: add IMyUserControl, the property and a parameter in the constructor to set the property.
So, all your forms implements now IMyUserControl. I don't know where are your forms but it's sure that you have a way to get access to your UserControl. Maybe a variable or an array in which you add your user controls. You are working with them, so you can access to your user controls. Well, if you have an UserControl instance, and you know that your UserControl implements IMyUserControl, you can cast your UserControl to IMyUserControl and after the cast, you have access to the interface, in this case, to the MyMiddle property.
And we put in MyMiddle all the code that you want to share.
If you add some code of your main form, where you work with your forms, I can help you with the code. I haven't more code than existing in my answer.
I am trying to add several controls like Labels, pictureboxes etc. to a Panel in c# Windows Forms. My code looks like this:
this.panel1.Controls.Add(this.label1);
Every time I put this in the panel1 section in my Designer.cs, it gets deleted after I switch between classes and forms. I am doing this so that I can "transform" the Panel into a Bitmap with all the other controls in it.
Well, as you can see, you are trying to modify code within
#region Windows Form Designer generated code
...
// Designer is supposed to put (or/and remove) any code within this region
// Do not put any custom code here manually
this.panel1.Controls.Add(this.label1);
...
#endregion
and you have a conflict with Designer. Just let it generate its code in the area which specially designed (and marked out) for that; put yours into, say, constructor:
public MyForm() {
// Let .Net initialize the form, create all constrols etc. first
InitializeComponent();
// Then, run your code here
this.panel1.Controls.Add(this.label1);
}
Try :
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.panel1.Controls.Add(this.label1);
}
}
I am truly destroyed by this principle that I will now explain. I did use the code for the answer mentioned in this article (Combo box drop down width on suggest).
The code works fine when it comes to inheriting a ComboBox. Exactly as in the following code:
public class ComboBoxEx : ComboBox
{
... //(See the code in the post: https://stackoverflow.com/questions/4820429/combo-box-drop-down-width-on-suggest)
private class ACWindow : NativeWindow
{
....
}
}
Well, as I said above, if I use the ComboBoxEx class in my Forms, this works fine: I can handle the size of the AutoComplete window.
But if I use the ComboBoxEx class in a UserControl and then insert UserControl into my Form, it will no longer work.
From various attempts I understand (perhaps) that the WndProc method of the ACWindow class is not executed for any reason.
Why are not Windows messages forwarded to UserControl's children controls?
In other words, the code I use is almost the following:
// UserCOntrol class declaration
public class MyCmbControl : UserControl
{
ComboBoxEx ExtendedCombo = new ComboBoxEx();
....
}
// Form class declaration
public class MyForm : Form
{
protected ComboBoxEx Cmb1 = new ComboBoxEx(); //-- This work fine!!
protected MyCmbControl Cmb2 = new MyCmbControl(); //-- This will no longer work
}
NOTE:
The UserControl control has the ComboBoxEx control as the only child
I tried to move the ACWindows class at UserControl level
I tried sending a 0x0047 (WM_WINDOWPOSCHANGED) message to the ComboBoxEx member of MyCmbControl
All this without getting good results...
I thank you in advance for the help you will give me and I apologize for the incorrect english I'm using in this post !!!
I'm using WinForms : C# .NET.
I'm facing a problem with ContextMenuStrip and Toolstrip. Visual Stuido's Property editor is not letting me to change the property I want.
Here is the snapshot of how I want my ContextMenuStrip to looklike & same is the case with Toolstrip. I don't understand how to do this.
If I need to learn something, please suggest appropriate good material (tutorials, articles etc.)
alt text http://f.imagehost.org/0289/KproxyChecker.jpg
You'll have to assign the Renderer property to a class that renders the CMS or tool strip the way you want it. Use this code as a template to get started:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
contextMenuStrip1.Renderer = new myRenderer();
}
class myRenderer : ToolStripProfessionalRenderer {
protected override void OnRenderToolStripBackground(ToolStripRenderEventArgs e) {
// Replace this with your own drawing code...
base.OnRenderToolStripBackground(e);
}
}
}
There is no single property that you can set to make a ContextMenuStrip look like that.
You need to create your own ToolStripRenderer class that paints menus like that, then set the Renderer property of the ContextMenuStrip to an instance of your ToolStripRenderer.
Good luck.
EDIT: You can find sample code here.
I have a question about extending a custom control which inherits from UserControl.
public partial class Item : UserControl
{
public Item ()
{
InitializeComponent();
}
}
and I would like to make a control which inherits from Item
sg like that
public partial class ItemExtended : Item
{
public ItemExtended():base()
{
InitializeComponent();
}
}
This works perfectly of course and the heritage works but my problem is in the designer
I just cannot open this ItemExtended in Design....
it says : Constructor on Type "Item" not found.
Does sy have an explanation?
is the best way to do it?
Thx
I'm of course using c# on .NET Winform :)
you invoke InitializeComponent() twice with calling InitializeComponent() on the very derived usercontrol.
This may lead to problem.
And there is some help property callad IsDesign or Design (something similar) of UC, which helps to avoid unnecessary UI operations on design time (in VS).
Edit: it is DesignMode. You can avoid to run RT functions by Design. Like if (!this.DesignMode) InitializeComponents();
You can also check this forumpost. http://www.c-sharpcorner.com/Forums/ShowMessages.aspx?ThreadID=41254