How to access Winform textbox control from another class

Question

I have a winform called Form1 and a textbox called textBox1  In the Form1 I can set the text by typing   textBox1 text    change text     Now I have created another class  How do I call textBox1 in this class  so I want to change the text for textBox1 in this class   How can I access the Form1 from this new class

User · Answer

Form1 form   new Form1     form textBox1 Text    test

User · Answer

You can change the access modifier for the generated field in Form1 Designer cs from private to public  Change this  private System Windows Forms TextBox textBox1    by this  public System Windows Forms TextBox textBox1    You can now handle it using a reference of the form Form1 textBox1   Visual Studio will not overwrite this if you make any changes to the control properties  unless you delete it and recreate it   You can also chane it from the UI if you are not confortable with editing code directly  Look for the Modifiers property

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I was also facing the same problem where I was not able to appendText to richTextBox of Form class   So I created a method called update  where I used to pass a message from Class1     class  Form1 cs  public partial class Form1   Form               public Form1                         InitializeComponent                 Form1   this                    public static Form1  Form1           public void update string message                        textBox1 Text   message                     private void Form1 Load object sender  EventArgs e                        Class1 sample   new Class1                                  class  Class1 cs  public class Class1                       public Class1                         Form1  Form1 update  change text

User · Answer

Take the Active form to a form variable  Form F1   myForm1 ActiveForm    Findout the Conntrol and Change the properties F1 Controls Find  quot Textbox1 quot   true  ElementAt 0  Text   quot Whatever you want to write quot

User · Answer

I Found an easy way to do this I ve tested it it works Properly  First I created a Windows Project on the form I Inserted a TextBox and I named it textBox1 then I inserted a button named button1 then add a class named class1  in the class1 I created a TextBox   class class1            public static TextBox txt1 new TextBox       a global textbox to interfece with      form1     public static void Hello                  txt1 Text  Hello                   Now in your Form Do this   public partial class Form1   Form            public Form1                InitializeComponent                  private void button1 Click object sender  EventArgs e                 class1 txt1 textBox1         class1 Hello                     in the button1 Click I coppied the object textBox1 into txt1 so now txt1 has the properties  of textBox1 and u can change textBox1 text in another form or class

User · Answer

Use  a global variable or property for assigning the value to the textbox  give the value for the variable in another class and assign it to the textbox text in form class

User · Answer

public partial class Form1   Form        public static Form1 gui      public Form1                 InitializeComponent            gui   this             public void WriteLog string log                this Invoke new Action      gt    txtbx test1 Text    log                public class SomeAnotherClass       public void Test                 Form1 gui WriteLog  1234              I like this solution

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What about   Form1 textBox1 text    change text    note  1  you have to  include  Form1 to your second form source file by  using Form1    textBox1 should be public

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Form frm1   new Form1    frm1 Controls Find  control name  true  0  Text    I changed this from another form

User · Answer

You will need to have some access to the Form s Instance to access its Controls collection and thereby changing the Text Box s Text   One of ways could be that You can have a Your Form s Instance Available as Public or More better Create  a new Constructor For your Second Form and have it receive the Form1 s instance during initialization

User · Answer

If your other class inherits Form1 and if your textBox1 is declared public  then you can access that text box from your other class by simply calling   otherClassInstance textBox1 Text    hello world

User · Answer

Define a property of the form like  then use this in other places it would be available with the form instance  public string SetText     get   return textBox1 Text      set   textBox1 Text   value

User · Answer

I used this method for updating a label but you could easily change it to a textbox   Class   public Class1       public Form Class formToOutput       public Class1 Form Class f           formToOutput   f                Then call this method and pass whatever string     private void Write string s                formToOutput MethodToBeCalledByClass s             Form methods that will do the updating   public Form Class          Methods that will do the updating     public void MethodToBeCalledByClass string messageToSend               if  InvokeRequired                Invoke new OutputDelegate UpdateText  messageToSend                        public delegate void OutputDelegate string messageToSend       public void UpdateText string messageToSend               label1 Text   messageToSend            Finally  Just pass the form through the constructor   Class1 c   new Class1 this

User · Answer

I would recommend that you don t  Do you really want to have a class that is dependent on how the text editing is implemented in the form  or do you want a mechanism allowing you to get and set the text   I would suggest the latter  So in your form  create a property that wraps the Text property of the TextBox control in question   public string FirstName       get   return firstNameTextBox Text        set   firstNameTextBox Text   value        Next  create some mechanism through which you class can get a reference to the form  through the contructor for instance   Then that class can use the property to access and modify the text   class SomeClass       private readonly YourFormClass form      public SomeClass YourFormClass form                this form   form             private void SomeMethodDoingStuffWithText                 string firstName   form FirstName          form FirstName    some name             An even better solution would be to define the possible interactions in an interface  and let that interface be the contract between your form and the other class  That way the class is completely decoupled from the form  and can use anyting implementing the interface  which opens the door for far easier testing    interface IYourForm       string FirstName   get  set        In your form class   class YourFormClass   Form  IYourForm          lots of other code here      public string FirstName               get   return firstNameTextBox Text            set   firstNameTextBox Text   value                 and the class   class SomeClass       private readonly IYourForm form      public SomeClass IYourForm form                this form   form                and so on

User · Answer

I tried the examples above  but none worked as described  However  I have a solution that is combined from some of the examples   public static Form1 gui  public Form1         InitializeComponent        gui   this      comms   new Comms       public Comms         Form1 gui tsStatus Text    test       Form1 gui addLogLine  Hello from Comms class        Form1 gui bn connect Text    Comms       This works so long as you re not using threads  Using threads would require more code and was not needed for my task

[c#] How to access Winform textbox control from another class?

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