I have a windows forms application with some controls added to the designer. When I want to change something (LIKE) enabling a text box from inside the Form1.cs, I simply use:
textBox1.Enabled = true;
but now I have a separated class called class1.cs.
How could I enable textBox1 from a static function class1.cs?
NOTE: I did not try any code because I am totally clueless about doing this.
EDIT: Lot of edit.
public partial class Form1 : Form
{
// Static form. Null if no form created yet.
private static Form1 form = null;
private delegate void EnableDelegate(bool enable);
public Form1()
{
InitializeComponent();
form = this;
}
// Static method, call the non-static version if the form exist.
public static void EnableStaticTextBox(bool enable)
{
if (form != null)
form.EnableTextBox(enable);
}
private void EnableTextBox(bool enable)
{
// If this returns true, it means it was called from an external thread.
if (InvokeRequired)
{
// Create a delegate of this method and let the form run it.
this.Invoke(new EnableDelegate(EnableTextBox), new object[] { enable });
return; // Important
}
// Set textBox
textBox1.Enabled = enable;
}
}
This is just another method:
TextBox t = Application.OpenForms["Form1"].Controls["textBox1"] as TextBox;
You shouldn't really change UI controls in your Form from your class1, but instead create a method or a property in class1 that would tell if the textbox should be enabled or not.
Example:
// I changed the name class1 to MySettings
public class MySettings
{
public bool ShouldTextBoxBeEnabled()
{
// Do some logic here.
return true;
}
// More generic
public static bool SetTextBoxState(TextBox textBox)
{
// Do some logic here.
textBox.Enabled = true;
}
// Or static property (method if you like)
public static StaticShouldTextBoxBeEnabled { get { return true; } }
}
Then in your form:
MySettings settings = new MySettings();
textBox1.Enabled = settings.ShouldTextBoxBeEnabled();
// Or static way
textBox1.Enabled = MySettings.StaticShouldTextBoxBeEnabled;
// Or this way you can send in all textboxes you want to do the logic on.
MySettings.SetTextBoxState(textBox1);
You can pass the instance of your Form to the class
MyForm frm = new MyForm();
MyClass c = new MyClass(frm);
Then your class can take that instance and access the textbox
public class MyClass
{
public MyClass(MyForm f)
{
f.TextBox1.Enabled = false;
}
}
The design does not look OK
It is better to call the class in your form and based on the value returned, manipulate the textbox
//MyForm Class
MyClass c = new MyClass();
c.DoSomethings();
if(c.getResult() == requiredValue)
textBox1.enabled = true;
else
textBox1.enabled = false;
//MyForm Class ends here
UPDATE
public class Class1
{
public static int SomeFunction()
{
int result = 1;
return result;
}
public static void SomeFunction(out int result)
{
result = 1;
}
}
Usage
if(Class1.SomeFunction() == 1)
textBox1.Enabled = true;
else
textBox1.Enabled = false;
OR
int result = 0;
Class1.SomeFunction(out result);
if(result == 1)
textBox1.Enabled = true;
else
textBox1.Enabled = false;
You could let your class1 have an event to enable the Textbox.
public class Class1
{
public event Action<object, EventArgs> subscribe ;
private void raiseEvent()
{
var handler = subscribe ;
if(handler!=null)
{
handler(this,EventArgs.Empty);//Raise the enable event.
}
}
}
Let the class containing the TextBox subscribe to it somehow. In TextBox wrapper class
public class TextBoxWrapper
public void EnablePropertyNotification(object sender, EventArgs args)
{
TextBox1.Enabled = true ; //Enables textbox when event is raised.
}
public TextBoxWrapper()
{
class1Instance.subscribe+=EnablePropertyNotification ;
}
To access/modify a Form Element property, just write this in your outside Class.
Form1.ActiveForm.Controls["textBox1"].Enabled = true;
Where textBox1 is the variable name of TextBox.
What this actually does: Gets the active Form object's control specified by the name in string.
WARNING: Active form means the form which is currently open and focused on. If you do something else on your computer, with your minimized WindowsForm application, the Form1.ActiveForm will not get the form, instead, it will give null, which can lead to errors later. Be careful!
based on the answer from @vr_driver you can do that to avoid problems with other containers like groupbox, panels...
TextBox t = Application.OpenForms["Form1"].Controls.Find("textBox1", true)[0] as TextBox;
In this example you have a form called Main.cs and a class called MyClass:
In MyClass (Note: the name of my Form Class = 'Main'):
Main ui = new Main();
ui.toolStripProgressBarStickers.PerformStep();
In (FormName).Designer.cs so in my case Main.designer.cs change the appropriate control from 'private' to 'public':
public System.Windows.Forms.ToolStripProgressBar toolStripProgressBarStickers;
This solved it for me. Thanks, Ensai Tankado
I had to do this at work and didn't find that any of these answers matched what I ended up doing, so I'm showing how I made it work.
First, initialize a copy of your class in your load event.
NameOfClass newNameofClass;
Then you want to bind to your class (in the load event):
textBox1.DataBindings.Add(new Binding("Enabled", newNameofClass, "textBox1Enabled"));
In your class, do the following:
private bool textBox1Enabled = false;
public bool TextBox1Enabled
{
get
{
return textBox1Enabled;
}
set
{
textBox1Enabled = value;
}
}
Very easy:
Create an Instance of your Form Object where want to access the Elements from.
Form1 ui = new Form1();
and now change the Form Elements to "public" - like this in the Designer Code:
...
public System.Windows.Forms.TextBox textBox6;
...
Now you can access them like this in your Code:
ui.textBox6 ...
I had the same problem. I used windows forms & Visual Studio to generate a UI in a utility with textbox, checkbox, and button controls but ALL the code was in the same class.
I'm rewriting the utility now that I know "more" OOP concepts and created actual objects and separate classes. I too had problems getting the separate classes to be able to access the form controls and any shared methods that are in the form class. I tried the various suggestions in this thread as well as other threads but none of those solutions worked for me.
What worked for me (not sure if its the right thing to do or not) was I had each class that needed to access the controls and forms methods inherit from the Form. Here is the relevant part of the Form.cs file:
namespace Utility
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void WriteNote(string noteText, bool asHeading = false)
{
//Writes Messages to the Message box in the UI
Font font1 = new Font(this.ResultsTB.Font, FontStyle.Bold);
Font font2 = new Font(this.ResultsTB.Font, FontStyle.Regular);
if (asHeading)
this.ResultsTB.Font = font1;
else
this.ResultsTB.Font = font2;
this.ResultsTB.AppendText(noteText + "\r\n");
}
My Form contains a textbox called DirTB and a method called "WriteNote" that writes info to another textbox called ResultsTB. Here is the class (at least as far down as the first successful call of the WriteNote method from the Form:
namespace Utility
{
public class AppServerDTO : Form1
{
#region App Server attributes
//attributes listed here
#endregion App Server attributes
#region AppServerDTO Constructor
public AppServerDTO()
{
//These methods verify and set all the attributes
VerifyInstallFolder();
}//end of constructor AppServer
#endregion AppServerDTO Constructor
#region AppServerDTO class methods
public void VerifyInstallFolder()
{
string keypath = string.Empty;
string locationVerification = DirTB.Text + @"\SomeText";
for (int i = 0; i < 4; i++) //allows 3 attempts to get the install folder right
{
if (Directory.Exists(locationVerification))
{
i = 4;//Kills the loop
}
else if (!Directory.Exists(locationVerification))
{
locationVerification = DirTB.Text + @"\SomeMoreText";
}
else if (!Directory.Exists(locationVerification))
{
WriteNote("The directory listed in the Install Directoy box is not reachable.");
WriteNote("Please select the correct directory.");
WriteNote("The correct directory is the folder that contains the ApplicationUpdates & UpdateManager folders.");
WriteNote(@"i.e. C:\Somewhere or D:\Someplace\Somewhere");
var folderpath = FolderPrompt(@"C:\");
DirTB.Text = folderpath; //updates the install folder textbox to the new location
keypath = folderpath;
i++;
}
}//end for loop
}//end VerifyInstallFolder
As long as you are very careful with what you mark as public vs private, it should be ok.
This is how you should do : I wrote the code below in my form class :
public static Form1 form = null;
private delegate void SetImageDelegate(Image image);
public Form1()
{
InitializeComponent();
form = this;
}
public static void SetStaticImage(Image image)
{
if (form != null)
form.pic1.Image = image;
}
private void setImage(Image img)
{
// If this returns true, it means it was called from an external thread.
if (InvokeRequired)
{
// Create a delegate of this method and let the form run it.
this.Invoke(new SetImageDelegate(setImage), new object[] { img });
return; // Important
}
// Set textBox
pic1.Image = img;
}
and the code below should be in anouther class :
Form1 frm= Form1.form;
frm.pic1.Image = image;
Note that i changed private static Form1 form = null; to public static Form1 form = null;
Good Luck ... Written by Hassan Eskandari :)
