从c＃winform中的另一个类调用标签文本

Question

I am currently updating my Form with this code within the public partial class Form1 : Form

this.Invoke((MethodInvoker)delegate
{
    Intellisale_Lastprocessed_Item_Label.Text = "example"
}

since I have tons of UI elements I would rather get all my ui update code into another class.

Therefore I built the class "UiUpdate".
unfortunately from within this class i receive the message: "Form 1 does not contain a definition for Intellisale_Lastprocessed_Item_Label"

Probably I have overlooked something really easy but I have not found the answer yet.

EDIT:

Due to the Suggestions I changed my code to the following:

class UiUpdate
{
    public void UpdateIntellisale(Form1 form)
    {
        form.Intellisale_Lastprocessed_Item_Label.text = "example";
    }
}

unfortunately i still receive the message that no definition for the lable is available

Update 2:

as mentioned, the lables were defined private within the designer

Answer 1

You're making a static reference to the Form1 class , not to a particular instance of that class. Pass the instance you need to your method:

public void UpdateIntellisale(Form1 form)
{
    form.Intellisale_Lastprocessed_Item_Label.Text = "test";
    // etc...
}

When you call it from your form you would pass it the reference to your form. Which may be this if called from the form itself. Basically you need your helper class/method to know what form it's working with.

Answer 2

You need to pass the object of Form1 class into UpdateIntellisale method. Like:

class UiUpdate {
    public void UpdateIntellisale(Form1 form) {
        form.Intellisale_Lastprocessed_Item_Label.text = "test";
    }
}

And call it like: UpdateIntellisale(this) (of course only if this is of Form1 class)

Answer 3

there are several issues: 1. You address your label as if it was defined as a static member of Form1. Use the instance name instead. eg:

Form1 form = new Form1();
form.Intellisale_Lastprocessed_Item_Label.Text = "example" 
// Be aware of an InvalidOperationException with the message, "Control control name accessed from a thread other than the thread it was created on." that is throw if you use this code.

see: https://docs.microsoft.com/en-us/dotnet/framework/winforms/controls/how-to-make-thread-safe-calls-to-windows-forms-controls

2. Usually the labels are defined private in the designer file. The easy way is to declare them public, but it is not a good thing to address a field directly from some other class. Use a Property instead.