How can I make a textbox in my winforms application that accepts new lines of text from anywhere in the application?
I have a main form that contains a textbox. I'd like to directly add text to the box from a method in another class.
Update
I tried this in my main form:
public void Output(String value)
{
if (txtOutput.Text.Length > 0)
{
txtOutput.AppendText(Environment.NewLine);
}
txtOutput.AppendText(value);
}
But I can't call Output from the other class. I'm new to C#, so perhaps I'm missing something obvious.
Regards, Miel.
PS Yes, I know this is bad design, but for now this seems to be the best way to do what I want. The textbox would function like a console.
You'll need to expose the Text property of the TextBox as a string property on your form. For example...
public string TextBoxText
{
get { return textBoxName.Text; }
set { textBoxName.Text = value; }
}
Edit
After reading the question edit, your problem is that you need a reference to a specific instance of the form whereever you're trying to execute that code. You can either pass around a reference (which is the better option), or you could use some smelly code and have a static property that refers to one instance of your form. Something like...
public partial class MyForm : Form
{
private static MyForm instance;
public static MyForm Instance
{
get { return instance; }
}
public MyForm() : base()
{
InitializeComponent();
// ....
instance = this;
}
}
Using this approach, you could call MyForm.Instance.Output("test");
In order to decouple a bit more you could inverse the control a bit:
// interface for exposing append method
public interface IAppend
{
void AppendText(string text);
}
// some class that can use the IAppend interface
public class SomeOtherClass
{
private IAppend _appendTarget = null;
public SomeOtherClass(IAppend appendTarget)
{
_appendTarget = appendTarget;
}
private void AppendText(string text)
{
if (_appendTarget != null)
{
_appendTarget.AppendText(text);
}
}
public void MethodThatWillWantToAppendText()
{
// do some stuff
this.AppendText("I will add this.");
}
}
// implementation of IAppend in the form
void IAppend.AppendText(string text)
{
textBox1.AppendText(text);
}
It looks like your design is a little bit corrupted. You shouldn't let buisness logic mess with GUI controls. Why don't you try a return value and assigning it on the interface side?
This is a REALLY bad way of doing it, but just to make sure all the answers are out there...
In the VS designer, each form control has an item in the Properties window named Modifiers that defaults to Private. Changing this to one of the others settings, such as Internal or Public, will let you access it from outside the form.
I must stress that this is the worst way to do it.
Related
I'd like to add a WinForm into my Console App:
namespace ExchangeNativeDemo.Window
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
}
}
I would like to pass textbox1 value to Program.cs, like:
var emailaddress = textbox1.value
In program.cs:
using ExchangeNativeDemo.Window;
namespace ExchangeNativeDemo
{
class Program
{
static void Main(string[] args)
{
But I got the error:
is inaccessible due to its protection level
What I missed?
When you add a TextBox (or other control) to a WinForm using Visual Studio, the control is defaulted to protected scope, meaning that the only code that can access it is the code in the WinForm itself or classes that derive from it.
There are two common options:
Just change the TextBox from protected to public. This breaks encapsulation a bit so this isn't my favorite.
Write a custom property that exposes the textbox's Text property, e.g.
class Form1
{
//.....Other stuff....
public string Text1Value
{
get { return this.textbox1.Text; }
}
}
Since you know that it is supposed to be the email address, and you want to at least try to be a little encapsulated, you might actually want to name it EmailAddressEntered or something similar.
public string EmailAddressEntered
{
get { return this.textbox1.Text; }
}
Then in your main program, create an instance of the form, display it, then read the property.
void Main()
{
//....do other stuff....
var form = new Form1();
form.ShowDialog();
var emailaddress = form.EmailAddressEntered;
}
Also note, a TextBox does not have a Value. The contents are stored in the Text property instead.
Also also note, your main function should contain a call to Application.Run or you'll find that Form1 doesn't work very well.
You need to make textbox1 public,
or add property to `Form1 that will expose its value:
public string Textbox1Text
{
get { return textbox1.Text; }
}
I believe you need to declare your var as public otherwise it is automatically private. Try and let me know.
I'm wondering if it is possible to access a textbox value from another class inside a C# winform.
For example, at the moment I have a bunch of different textboxes I'm turning on and off all within my Form1.cs class like so:
screentextBox.Visible = true;
However, to cut down on the amount of lines of code within my C# class I was wondering is it possible to make this call from another class, then in my Form1.cs call my other classes method?
Something like:
class Otherclass
{
public void ShowTextBox()
{
screentextBox.Visible = true;
}
}
Then in my Form1.cs simply call my new ShowTextBox method.
I'm sorry if this is a silly question, but I've looked around google and I couldn't find anything that could help me out.
You could pass the TextBox as a parameter to a function in another class:
class OtherClass
{
public void ShowTextBox(TextBox target)
{
target.Visible = true;
}
}
However, I would advise to keep all the methods and code pertaining to handling the GUI and its events inside the form itself. If you have large methods for calculations, etc., than those can be moved to other classes.
you can Make ScreentextBox as Public in Declaring class and access it in Another class like
class Otherclass
{
public void ShowTextBox()
{
Class1.ScreenTextBox.Visible =true;
}
}
You could define the ShowTextBox method in a partial class So you still have the access to the control and also tidy your code.
Add method for showing TextBox in your form:
public partial class Form1 : Form
{
public void ShowTextBox()
{
screentextBox.Visible = true;
}
}
and then pass your From1 to other forms and call this method from there.
Class OtherClass
{
public static void method(TextBox[] items)
{
foreach(item in items)
{
(item as TextBox).Visible = true;
}
}
}
to call this method from ur Form1.cs class--->
OtherClass.method( new TextBox[] { TxtBox1, TxtBox2, TxtBox3 } );
If you want to access the controls of Form1.cs from another class try this way
class Otherclass
{
Form1 f1 = new Form1();
f1.Controls["screentextBox"].Visible = true;
}
I would do it like this (example from John Willemse):
class OtherClass
{
public TextBox ShowTextBox(TextBox target)
{
target.Visible = true;
return target;
}
}
Yet another approach to this old problem: I've found that the old way is an easy way to make accessible controls (including all their properties and methods), and perhaps other variables, from any class within the project. This old way consists of creating an ad hoc class from scratch.
Note A: about the old way: I know, I know, global variables are evil. But, for many people coming here looking for a fast/flexible/suites-most-cases solution, this may be a valid answer and I have not seen it posted. Another thing: this solution is what I am actually using as the answer for what I came to this page looking for.
1st step: The new class file from scratch is below.
namespace YourProjectNamespace
{
public class dataGlobal
{
public System.Windows.Forms.TextBox txtConsole = null;
// Place here some other things you might want to use globally, e.g.:
public int auxInteger;
public string auxMessage;
public bool auxBinary;
// etc.
}
}
Note B: The class is not static nor has static members, which allows to create several instances in case it is needed. In my case I do take advantage of this feature. But, as a matter of fact, you may consider making this class' TextBox a public static field so that -once initialized- it is always the same throughout the application.
2nd step: Then you're able to initialize it in your Main Form:
namespace YourProjectNamespace
{
public partial class Form1 : Form
{
// Declare
public static dataGlobal dataMain = new dataGlobal();
public Form1()
{
InitializeComponent();
// Initialize
dataMain.txtConsole = textBox1;
}
// Your own Form1 code goes on...
}
}
3rd step: And from your other class (or form), the call to any property/method of Form1's textBox1:
namespace YourProjectNamespace
{
class SomeOtherClass
{
// Declare and Assign
dataGlobal dataLocal = Form1.dataMain;
public void SomethingToDo()
{
dataLocal.txtConsole.Visible = true;
dataLocal.txtConsole.Text = "Typing some text into Form1's TextBox1" + "\r\n";
dataLocal.txtConsole.AppendText("Adding text to Form1's TextBox1" + "\r\n");
string retrieveTextBoxValue = dataLocal.txtConsole.Text;
// Your own code continues...
}
}
}
[EDIT]:
A simpler approach, specifically for the TextBox visibility throughout classes, I have not seen in other answers:
1st step: Declare and initialize an auxiliary TextBox object in your Main Form:
namespace YourProjectNamespace
{
public partial class Form1 : Form
{
// Declare
public static TextBox txtConsole;
public Form1()
{
InitializeComponent();
// Initialize
txtConsole = textBox1;
}
// Your own Form1 code goes on...
}
}
2nd step: And from your other class (or form), the call to any property/method of Form1's textBox1:
namespace YourProjectNamespace
{
class SomeOtherClass
{
public void SomethingToDo()
{
Form1.txtConsole.Visible = true;
Form1.txtConsole.Text = "Typing some text into Form1's TextBox1" + "\r\n";
Form1.txtConsole.AppendText("Adding text to Form1's TextBox1" + "\r\n");
string retrieveTextBoxValue = Form1.txtConsole.Text;
// Your own code continues...
}
}
}
Comment to the [Edit]: I have noticed that many questions simply cannot be solved by the usual recommendation: "instead, make public properties on your form to get/set the values you are interested in". Sometimes there would be several properties/methods to implement... But, then again, I know... best practices should prevail :)
This should be quite simple really - not sure what the problem is.
I have a C# Class (Public.cs) and a windows form (Form1.cs). Through a function in Public.cs, I want to get the value of a control on Form1 (without having to use object parameters).
// This code appears in Public.cs
public string MyFunction(int num_val)
{
if (chk_num.checked == true)
{
// Something here...
}
}
The issue is that my class cannot find the control on my form. Is there some way that I must reference it in C#?
Thank you.
I would strongly suggest exposing the Checked property via a specific property on Form1 (perhaps with a more meaningful name). This will help to hide the implementation details (i.e. control structure) of the Form1 from it's caller and instead expose only the logic that is required for other consumers to do their job
For example:
public bool IsNumberRequested
{
get { return chk_num.Checked; }
}
Or alternatively, if you still really want to access the control directly, from the designer you can select the control and change it's Modifier property to public (or something else) enabling you to access the control object using the code you originally wrote above.
EDIT: (Response based on comment)
Public.cs will still need a reference to Form1 and then will call the IsNumberRequested property of that object.
// Public.cs
public class Public
{
private Form1 _ui;
public Public(Form1 ui) { _ui = ui };
public string MyFunction(int num_val)
{
if (_ui.IsNumberRequested)
{
// Stuff
}
// Else, default Stuff
}
}
Alternatively, you could pass the form as a parameter to the MyFunction too rather than using it as an instance variable.
I would have the set up the other way around
public class Public
{
public bool CheckNumber {get;set;}
public string MyFunction(int val)
{
if(CheckNumber)
{
//do that thing
}
return ...
}
}
public partial class Form1 : Form
{
Public myinstance = new Public();
public Form1()
{
InitializeComponent();
}
private void CheckBoxChanged(object sender, EventArgs e)
{
myinstance.CheckNumber = chk_num.checked;
}
}
You'll need to assign CheckBoxChanged to the OnChanged event handler for your check box (which I'm assuming is chk_num.
This way your class Public doesn't rely on a form, which it shouldn't.
As Reddog says, use better names, although I half suspect you've just given example names in your question.
I almost never used (advanced, or at all) graphical interfaces, or one simple form with simple controls... but this time I've got something a little more complex, and I don't have much experience with GUI.
I have one main form (and possibly more in the future) from which other sub-forms open (and they might have sub-forms of themselves) and I wonder what is, in your opinion, the best way to communicate between them?
I thought of passing the main form as a parameter to the constructors of the sub-forms, but it doesn't seem like a good way, especially if I'm going to need to communicate between other, distinct, sub-forms, not to mention I have to double check the input, or make a few methods, but it seems more like functional programming than object oriented programming...
Perhaps I can:
Create a static class (or Properties.Settings) for global settings. Cons: every change of data is needed to be copied to the class, I'm looking for something a bit more comfortable and elegant.
Use the ugly way of accessing the controls from Application.OpenForms - fixes the problem of passing the main form as parameter. Cons: not very stable.
Do something else I haven't thought of. Suggestions? Cons: don't know what it is yet.
Your constructor idea is probably the most sound method of communication back to the main form. Your sub form would do something like the following:
public class SubForm : Form
{
public SubForm(MainForm parentForm)
{
_parentForm = parentForm;
}
private MainForm _parentForm;
private void btn_UpdateClientName_Click(object sender, EventArgs e)
{
_parentForm.UpdateClientName(txt_ClientName.Text);
}
}
And then you expose public methods on your MainForm:
public class MainForm : Form
{
public void UpdateClientName(string clientName)
{
txt_MainClientName.Text = clientName;
}
}
Alternatively, you can go the other way around and subscribe to events from your SubForms:
public class MainForm : Form
{
private SubForm1 _subForm1;
private SubForm2 _subForm2;
public MainForm()
{
_subForm1 = new SubForm1();
_subForm2 = new SubForm2();
_subForm1.ClientUpdated += new EventHandler(_subForm1_ClientUpdated);
_subForm2.ClientUpdated += new EventHandler(_subForm2_ProductUpdated);
}
private void _subForm1_ClientUpdated(object sender, EventArgs e)
{
txt_ClientName.Text = _subForm1.ClientName; // Expose a public property
}
private void _subForm2_ProductUpdated(object sender, EventArgs e)
{
txt_ProductName.Text = _subForm2.ProductName; // Expose a public property
}
}
A good way is to declare delegates in the form that want to start the communication. You need a delegate and a callback function:
public delegate void SetValueDelegate(string value);
public SetValueDelegate SetValueCallback;
Another form can then attach to this delegate. At that moment both forms have to know each other, but not after that moment:
firstForm.SetValueCallback += new SetValueDelegate(secondForm.SetValueFunction);
The second form has to declare a function that matches the delegate definition:
public void SetValueFunction(string value)
{
// do something
}
Now the first form can use the delegate to use the function of the second form (and all other forms or classes that were attached to the delegate:
SetValueCallback(txtParam.Text);
Edit: made an complete example
using System;
namespace DelegateTest
{
public delegate void SetValueDelegate(string value);
public class Class1
{
public SetValueDelegate SetValueCallBack;
public void Test()
{
if(SetValueCallBack != null)
{
SetValueCallBack("Hello World!");
}
}
}
public class Class2
{
public void SetValueFunction(string value)
{
Console.WriteLine(value);
}
}
public class Launcher
{
public static void Main(string[] args)
{
Class1 c1 = new Class1();
Class2 c2 = new Class2();
c1.SetValueCallBack += new SetValueDelegate(c2.SetValueFunction);
c1.Test();
}
}
}
The most flexible, scalable (and IMHO the most professional) way to do it is to use CAB (Composite Application Block). In simple terms CAB is a set of 2-3 assemblies that implement a lot of plumbing required to make complex UI applications the right way and it exposes this plumbing to the user of the library in a nice way. Among others it has a very nice event and command (as in command pattern) system.
The downside: requires some time to learn and not very trivial to grasp.
Here is a comprehensive (but easy to understand) tutorial that will help you make the learning easier.
You can use the built in Tag property of the form which is an "object" class.
public Form1()
{
(ComplicatedDataStructure)Tag = new ComplicatedDataStracture();
}
.
.
form1 = new Form1();
.
.
form2 = new Form2();
.
.
form2.Tag = form1.Tag;
so form2.Tag is equals to "ComplicatedDataStracture" object;
The case is this, I have two different forms from the same solution/project. What I need to do is to extract the value of a label in Form A and load it into Form B. As much as possible, I am staying away from using this code since it will only conflict my whole program:
FormB myForm = new FromB(label.Text);
myForm.ShowDialog();
What I am trying right now is a class with a property of get and set for the value I wanted to pass. However, whenever I access the get method from FormB, it returns a blank value.
I hope somebody can help me with this. Any other ways to do this is extremely appreciated. :)
public class Miscellaneous
{
string my_id;
public void SetID(string id)
{
my_id = id;
}
public string GetID()
{
return my_id;
}
}
You could do something like this:
Child form
public string YourText { get; set; }
public TestForm()
{
InitializeComponent();
}
public void UpdateValues()
{
someLabel.Text = YourText;
}
Initiate it
var child = new TestForm {YourText = someTextBox.Text};
child.UpdateValues();
child.ShowDialog();
With this approach you don't have to change the Constructor, you could also add another constructor.
The reason for them being empty is that the properties are set after the constructor, you could Also do someting like this to add a bit of logic to your getters and setters, However, I would consider not affecting UI on properties!
private string _yourText = string.Empty;
public string YourText
{
get
{
return _yourText;
}
set
{
_yourText = value;
UpdateValues();
}
}
In this case, the UI will be updated automaticly when you set the property.
You can use a static variable/method to hold/pass the value of a control (when it gets changed).
You can use form reference or control reference to get and pass values directly.
You can use custom event for that (notifying the code that subscribed).
btw. FormB myForm = new FromB(label.Text); did not work because you are passing by value and the value was empty at the moment of creation of FormB.
FormB myForm = new FromB(label); would have worked.
Well one approach to take is to create a singleton class in your application. When you form b loads or the label changes you update the singleton with the value. Then when form a needs the value it can just get the instance of the singleton within your application and it will have that value.
There are probably cleaner ways to do it but just thinking of an easy way to pass information back and forth and store any information needed for both forms.
EDIT: Here is an example of a singleton that I pulled from here:
http://www.yoda.arachsys.com/csharp/singleton.html
public sealed class Singleton
{
static readonly Singleton instance=new Singleton();
// Explicit static constructor to tell C# compiler
// not to mark type as beforefieldinit
static Singleton()
{
}
Singleton()
{
}
public static Singleton Instance
{
get
{
return instance;
}
}
}
Now all you need to do is put this class in a namespace that is accessible to both forms and then you can call the Instance property of this class and then reference your values. You can add properties to it as well for whatever you want to share. When you want to retrieve those values you would call it like this:
Singleton.Instance.YourProperty
((Form2)Application.OpenForms["Form2"]).textBox1.Text = "My Message";
declare public property varible in second form
Public property somevariable as sometype
and access it in first form using instance
Dim obj as New form2()
obj .somevariable ="value"