I'm working on a Windows Forms application in C# with Visual Studio 2010.
There is a form mainForm.
mainForm contains a tree view control xmlTreeView.
There is a self-written class myClass.cs.
Now, myClass needs to access the xmlTreeView. However I don't know a) how to access the form and b) which way would be best to do that.
I tried to implement an interface following oleksii's answer but I don't get it. The main form of the application is defined like this:
public interface IMainForm {
TreeView treeView { get; }
}
public partial class mainForm : Form, IMainForm {
public TreeView treeViewControl {
get { return myTreeViewControl; }
}
// Some code here
[...]
RuleTree rt = new RuleTree(); //How do I call this with the IMainForm interface???
}
Another class RuleTree is defined like this:
class RuleTree {
private readonly IMainForm mainForm;
public RuleTree(IMainForm mainForm) {
this.mainForm = mainForm;
}
}
How do I call the constructor of RuleTree with the IMainForm interface???
I would do the following. Don't see it as code, it's just so that you can understand, you can modify it accordingly.
public class MyClass
{
public void MyMethod(YourTreeViewControl treeview)
{
// Do what you need to do here
}
}
Then in your forms code behind just instantiate MyClass and pass an instance of your treeview to it, something like this:
MyClass myClass = new MyClass();
myClass.MyMethod(tvYourTreeViewControl);
Hope this makes sense :)
One of the possible approaches would be to use dependency injection here. MyClass would have a constructor that takes a Form parameter. Thus when you create MyClass it would have the form injected. For example:
Foo
{
Foo(){}
}
Bar
{
private Foo currentFoo;
Bar(Foo foo) //dependency injection
{
currentFoo = foo;
}
public void OtherMethod()
{
//do something with currentFoo
}
}
It will be better to use interfaces (or abstract classes), so instead of Foo you could inject IFoo, this largely decouples your classes, which is a good design decision.
I have commented my code please read comments, I can make solution available as well.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
///
//Declare a static form that will accesible trhought the appication
//create form called frmMain form or any other name
//
public static frmMain MainForm { get; private set; }
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
//comment out default application run
//Application.Run(new MainForm());
//create a new instance of your frmMain form
//inside your main form add a tree view
//Loacte this file "frmMain.Designer.cs"
//Change treeView1 from private to public
// public System.Windows.Forms.TreeView treeView1;
MainForm = new frmMain();
//before I show my form I'll change docking of my tree view from myClass
MyClass mine = new MyClass(); //done
MainForm.ShowDialog();
}
}
public class MyClass
{
public MyClass()
{
Program.MainForm.treeView1.Dock = DockStyle.Fill;
}
}
}
This is not possible to access asp.net server side controls into other class other then their cs class e.g
test.aspx is a page
you can access test page controls only in test.aspx.cs
Other then this class this is not possible.
Related
How to make an object of another class in MainClass.
namespace WpfApplication1
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
myClass obj = new myClass();
//obj.Show(); //not possible!!
}
public partial class myClass
{
void Show()
{
}
}
}
Now In this project, I can't access Show() method using "obj" object. How do I access method of another Class in this project??
You must declare Show as a public void to have access to the method.
namespace WpfApplication1
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
obj.Show(); //and must be inside of a method, function or constructor.
}
myClass obj = new myClass();
//obj.Show(); //not possible beacause is not a public method.!!
}
public partial class myClass
{
//public method.
public void Show()
{
}
}
}
After reading your comments I understood that you are new WPF, and confusing some concepts with Console Applications.
In Console Applications, the Main method acts as an entry point, and everything in the method is executed in an orderly fashion from top to bottom, unless some function calls are made. Consider the following example.
Static void Main(string[] args)
{
myClass obj = new myClass();
obj.Show();
}
This code is valid because when the Console Application starts it executes from top to bottom. I mean it creates a myClass object and calls Show method, but in WPF it's different. The only method that executes immediately like Main is MainWindow Constructor. The code after the constructor is not auto executed, unless they are properties, just like a Console Application. I mean the following code will not work properly in a console application.
Static void Main(string[] args)
{
myClass obj = new myClass();
}
obj.Show();
It's because Show method is called out side of the Main method and the program doesn't know what to do with it. Similarly in WPF, you have to call the Show method in the constructor.
public MainWindow()
{
InitializeComponent();
obj.Show();
}
There are many ways to call Show method in WPF, and the above mentioned way is only one of them. The logic Console Applications and Logic of WPF Applications are similar and different at the same time. I suggest you read a few articles or books on WPF to clear things up.
im writing an application in visual studio and im trying to access a rich text box from an other class. This doesnt seem to work for me. Also how to i call a function from an other class?
My code:
namespace Test{
public partial class Form1 : Form
{
public Form1()
{
// I want from this place to access the MyClass.test("hello");
}
}
}
namespace Test{
class MyClass
{
public void test (string text)
{
// here i want to do richtextbox1.clear(); but the textbox is not available
}
}
}
can be done in many ways. My favorite would be to declare the object of the "MyClass" class within "Form1" by passing the "this" pointer as an argument. Thus, the object of the "MyClass" class will have access to all the members and public functions "Form1". Included RichTextBox1.
namespace Test{
public partial class Form1 : Form
{
MyClass MyClassObject;
public Form1()
{
InitializeComponent();
MyClassObject=new MyClass(this);
MyClassObject.test("hello");
}
}
}
namespace Test{
class MyClass
{
Form1 parent;
public MyClass(Form1 parentForm)
{
parent=parentForm;
}
public void test (string text)
{
parent.richtextbox1.clear();
}
}
}
You don't want to do this. You can for example do it like this:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
var myClass = new MyClass(this.richtextbox1);
myClass.SetTextBoxText("hello");
}
}
class MyClass
{
RichTextBox _textBox;
public MyClass(RichTextBox textBox)
{
_textBox = textBox;
}
public void SetTextBoxText(string text)
{
_textBox.Clear();
_textBox.Text = text;
}
}
This uses constructor injection to pass the textbox to operate on to the contstructor. In Form1's constructor the MyClass is instantiated with a reference to the textbox, which is initialized in InitializeComponent(). Then when you call SetTextBoxText, the class clears the associated textbox's text and then sets it to the passed text.
This is more specific than the commonly suggested method: just pass the entire Form1 instance to MyClass's constructor after making the textbox public, but that way you cannot reuse MyClass for other forms.
But as you see, it's pretty pointless to do. You can let Form1 contain this.richttextbox1.Text = "hello"; directly.
It is not quite clear from your question, but I'm supposing your richtextbox1 is located at Form1.
By default all UI elements of form has private acess modifier - that's why you can't access your richtextbox1 from outer class.
You can change it's access mmodifier to public - but I strongly encourage you not to do it.
Instead write some method in Form1 class like
public void ClearRichTextBox()
{
richtextbox1.Clear();
}
and use it.
I have this class ClassMainForm and a form named MainForm. I made a method in my class, then inside of that is my codes like quantity1.Show. My question is, how do I call my function from class to my main form? I'd appreciate all your help.
ClassMainForm :
public void Visible()
{
GroupInstruction.Hide(); // <<== how do i call my controls in my MainForm?
quantity1.Show(); // <<== how do i call my controls in my MainForm?
}
Thanks Guys...
First create a new instance of your class:
ClassMainForm cmf = new ClassMainForm();
After this you can use cmf.NAMEOFYOURFUNCTION to call your function.
NAMEOFYOURFUNCTION = One of the methods/functions in your class.
With the cmf. u refer to your class, and after the dot u select the name of your method/function.
EDIT:
Placed a numerupdown on the form, and I called it numerUpDown1.
MAINFORM:
namespace Stack_Overflow_2
{
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
}
public NumericUpDown numericupdown()
{
return numericUpDown1;
}
}
}
CLASS:
namespace Stack_Overflow_2
{
class ClassMainForm
{
MainForm mf = new MainForm();
public void Visible()
{
mf.numericupdown().Show();
}
}
}
Can someone please let me know by some code how I can call a function located in the Form class from another class?
Some code will be of great help!
thanks
EDIT: This is my current code
public partial class frmMain : Form
{
//*******Class Instances*******
ImageProcessing IP = new ImageProcessing();
//********************
public void StatusUpdate(string text)
{
tlsStatusLabel.Text = text;
}//
public frmMain()
{
InitializeComponent();
}//
}
class ImageProcessing
{
private void UpdateStatusLabel(frmMain form, string text)
{
form.StatusUpdate(text);
}//
private UpdateLabel()
{
UpdateStatusLabel(frmMain, "Converting to GreyScale");
}
}
the problem i am having is with frmMain.
A quick and dirty way is to create a reference of the MainForm in your Program.cs file as listed above.
Alternatively you can create a static class to handle calls back to your main form:
public delegate void AddStatusMessageDelegate (string strMessage);
public static class UpdateStatusBarMessage
{
public static Form mainwin;
public static event AddStatusMessageDelegate OnNewStatusMessage;
public static void ShowStatusMessage (string strMessage)
{
ThreadSafeStatusMessage (strMessage);
}
private static void ThreadSafeStatusMessage (string strMessage)
{
if (mainwin != null && mainwin.InvokeRequired) // we are in a different thread to the main window
mainwin.Invoke (new AddStatusMessageDelegate (ThreadSafeStatusMessage), new object [] { strMessage }); // call self from main thread
else
OnNewStatusMessage (strMessage);
}
}
Put the above into your MainForm.cs file inside the namespace but separate from your MainForm Class.
Next put this event call into your MainForm.cs main class.
void UpdateStatusBarMessage_OnNewStatusMessage (string strMessage)
{
m_txtMessage.Caption = strMessage;
}
Then when you initialise the MainForm.cs add this event handle to your form.
UpdateStatusBarMessage.OnNewStatusMessage += UpdateStatusBarMessage_OnNewStatusMessage;
In any UserControl or form associated with the form (MDI) that you want to call, just us the following...
UpdateStatusBarMessage.ShowStatusMessage ("Hello World!");
Because it is static it can be called from anywhere in your program.
You can do that in easy way:
1- create public class and define public static variable like this:
class Globals
{
public static Form1 form;
}
2- in load function at the form write this line:
public partial class Form1 : Form
{
private void Form1_Load(object sender, EventArgs e)
{
Globals.form= this;
}
public void DoSomthing()
{
............
}
}
3- finally, in your custom class you can call all public functions inside the form:
public class MyClass
{
public void Func1()
{
Globals.form.DoSomthing();
}
}
I hope this code will be useful to you:)
It's quite easy. Either pass a reference to an existing form in the call, or create a new instance of your form and then call your method just like any other:
public class MyForm : Form
{
public void DoSomething()
{
// Implementation
}
}
public class OtherClass
{
public void DoSomethingElse(MyForm form)
{
form.DoSomething();
}
}
Or make it a static method so you don't have to create an instance (but it won't be able to modify open form windows).
UPDATE
It looks like the ImageProcessing class never gets a reference to the form. I would change your code slightly:
class ImageProcessing
{
private frmMain _form = null;
public ImageProcessing(frmMain form)
{
_form = form;
}
private UpdateStatusLabel(string text)
{
_form.StatusUpdate(text);
}
}
And then one small tweek in the Form constructor:
ImageProcessing IP = new ImageProcessing(this);
You will have to create a new Form instance and then call it using the instance. If it is static then you can just call it by calling Form1.Method().
Form1 form1 = new Form1();
form1.Method();
I would suggest you move this common method to some other class.
If it is common method to be used in the UI then create a base Form class and derive all your forms with this base form class. Now move this common method to the base form. You can then use the method from any of the Form derived from it.
If the method is not related to the UI, an from your example i understand that it's not, you can create another class that will contain this method and then use it in your Form class and in any other places where you want to use it.
I have a component I created in C# which had previously been using the default constructor, but now I would like it to have its parent form create the object (in the designer), by passing a reference to itself.
In other words, instead of the following in the designer.cs:
this.componentInstance = new MyControls.MyComponent();
I would like to instruct the form designer to create the following:
this.componentInstance = new MyControls.MyComponent(this);
Is it possible to achieve this (preferably through some attribute/annotation or something)?
Can't you simply use the Control.Parent property? Granted, it will not be set in the constructor of your control, but the typical way to overcome that is by implementing ISupportInitialize and doing the work in the EndInit method.
Why do you need the reference back to the owing control?
Here, if you create a new console application, and paste in this content to replace the contents of Program.cs, and run it, you'll notice that in .EndInit, the Parent property is correctly set.
using System;
using System.Windows.Forms;
using System.ComponentModel;
using System.Drawing;
namespace ConsoleApplication9
{
public class Form1 : Form
{
private UserControl1 uc1;
public Form1()
{
uc1 = new UserControl1();
uc1.BeginInit();
uc1.Location = new Point(8, 8);
Controls.Add(uc1);
uc1.EndInit();
}
}
public class UserControl1 : UserControl, ISupportInitialize
{
public UserControl1()
{
Console.Out.WriteLine("Parent in constructor: " + Parent);
}
public void BeginInit()
{
Console.Out.WriteLine("Parent in BeginInit: " + Parent);
}
public void EndInit()
{
Console.Out.WriteLine("Parent in EndInit: " + Parent);
}
}
class Program
{
[STAThread]
static void Main()
{
Application.Run(new Form1());
}
}
}
I don't know any way of actually having the designer emit code calling a non-default constructor, but here's an idea to get around it. Put your initialization code inside the default constructor of the parent form and use Form.DesignMode to see if you need to execute it.
public class MyParent : Form
{
object component;
MyParent()
{
if (this.DesignMode)
{
this.component = new MyComponent(this);
}
}
}