爲什麼text2.Text =「message」在我的代碼中不起作用？

Question

爲什麼text2.Text =「message」在我的代碼中不起作用？ 我想在函數中以這種方式工作，參見代碼。 我在Visual Stduio在C＃開發具有單聲道的Android

的源代碼：

using System; 
using Android.App; 
using Android.Content; 
using Android.Runtime; 
using Android.Views; 
using Android.Widget; 
using Android.OS; 

namespace ChatClient_Android 
{ 
[Activity(Label = "ChatClient_Android", MainLauncher = true, Icon = "@drawable/icon")] 
public class MainChat : Activity 
{ 
    protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 

     // Set our view from the "main" layout resource 
     SetContentView(Resource.Layout.Main); 

     // Get our button from the layout resource, 
     // and attach an event to it 
     EditText text2 = FindViewById<EditText>(Resource.Id.text2); 
    } 

    private void recieved() 
    { 
    text2.Text = "mesage"; // The text2 does not existe in this context 

    } 
} 

}

Answer 1

EditText text2聲明不是全局的，但該方法。把EditText text2;放在課堂上。

應該是這樣的：

public class MainChat : Activity 
{ 
    EditText text2; // <----- HERE 
    protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 
     SetContentView(Resource.Layout.Main); 
     text2 = FindViewById<EditText>(Resource.Id.text2); 
    } 

    private void recieved() 
    { 
    text2.Text = "mesage"; 

    } 
} 

Answer 2

text2是內部OnCreate定義，因此received對此一無所知。

您需要定義文本2爲一類領域，如：

public class MainChat : Activity 
{ 
    private EditText text2; 
    protected override void OnCreate(Bundle bundle) 
    { 
     base.OnCreate(bundle); 

     // Set our view from the "main" layout resource 
     SetContentView(Resource.Layout.Main); 

     // Get our button from the layout resource, 
     // and attach an event to it 
     text2 = FindViewById<EditText>(Resource.Id.text2); 
    } 

    private void recieved() 
    { 
    text2.Text = "mesage"; // The text2 does not existe in this context 

    } 
}