Xamarin Android無法分配文本值來編輯文本

Question

我是移動開發的新手。 我正在使用Visual Studio 2015在xamarin中使用android進行工作。現在，我正在遵循示例代碼並按照其中的描述進行操作。

當我嘗試為update布局中的edit text分配text值時，出現異常。 貝婁是我在其中分配值以edit text

void List_ItemClick(object sender, AdapterView.ItemClickEventArgs e)
    {
        click_Employee = e.Position + 1;
        ICursor c = dbHelper.getSingleEntry(click_Employee);
        c.MoveToFirst();
        name = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_NAME));
        email = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_EMAIL));
        phone = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_PHONE));
        designation = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_DESIGNATION));
        dName.Text = name;
        dEmail.Text = email;
        dPhone.Text = phone;
        dDesignation.Text = designation;
    }

在上面的代碼中，在dName.Text = name;處dName.Text = name;了異常dName.Text = name; 波紋管是錯誤的描述

System.NullReferenceException: Object reference not set to an instance of an object.

我的show complete data功能執行了相同的工作，但是一切都很好，不知道update功能正在發生什么

更新1

貝婁是我insert employee代碼

namespace AppwithDB.Resources
{
[Activity(Label = "insertEmployee")]
class insertEmployee : Activity
{
    EditText name, email, phone, designation;
    Button submitBtn;
    private SQLiteHelper dbHelper;

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        //Create your app here 

        SetContentView(Resource.Layout.insert);
        initialize();
        dbHelper = new SQLiteHelper(this);
        submitBtn.Click += submitBtn_Click;
    }


    private void submitBtn_Click(object sender, EventArgs e)
    {
        if (name.Text.ToString().Equals("") || email.Text.ToString().Equals("")|| phone.Text.ToString().Equals("") || designation.Text.ToString().Equals(""))
        {
            Toast.MakeText(this, "Fields Empty Found", ToastLength.Short).Show();
        }
        else
        {
            dbHelper.insertEmployee(name.Text.ToString(), email.Text.ToString(), phone.Text.ToString(), designation.Text.ToString());
            Toast.MakeText(this, "Data Stored Successfully", ToastLength.Short).Show();
            name.Text = " ";
            email.Text = " ";
            phone.Text = " ";
            designation.Text = " ";
        }
    }

    private void initialize()
    {
        name = (EditText)FindViewById(Resource.Id.empName);
        email = (EditText)FindViewById(Resource.Id.empEmail);
        phone = (EditText)FindViewById(Resource.Id.empPhone);
        designation = (EditText)FindViewById(Resource.Id.empDesignation);
        submitBtn = (Button)FindViewById(Resource.Id.insertEmpBtn);
    }
}}

更新2

貝婁是update employee的代碼

namespace AppwithDB.Resources
{
[Activity(Label = "updateEmployee")]
class updateEmployee:Activity
{
    ListView list; 
    EditText dName, dEmail, dPhone, dDesignation;
    String name, email, phone, designation;
    SQLiteHelper dbHelper;
    int click_Employee;
    Button upBtn;

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        // Create your application here
        SetContentView(Resource.Layout.update);
        initialize();
        dbHelper = new SQLiteHelper(this);
        System.Collections.ArrayList dataList = dbHelper.getALLEmployeesData();
        string[] myArr = (string[])dataList.ToArray(typeof(string));
        list.Adapter = new ArrayAdapter(this, Android.Resource.Layout.SimpleExpandableListItem1, myArr);

        list.ItemClick += List_ItemClick;

        upBtn.Click += delegate
        {
            dbHelper.updateEmployeeInfo(click_Employee, dName.Text.ToString(), dEmail.Text.ToString(), dPhone.Text.ToString(), dDesignation.Text.ToString());
        };

    }

    private void initialize()
    {
        list = (ListView)FindViewById(Resource.Id.listView1);
        dName = (EditText)FindViewById(Resource.Id.eName);
        dEmail = (EditText)FindViewById(Resource.Id.eEmail);
        dPhone = (EditText)FindViewById(Resource.Id.ePhone);
        dDesignation = (EditText)FindViewById(Resource.Id.eDesignation);
        upBtn = (Button)FindViewById(Resource.Id.updateEmploy);
    }
    void List_ItemClick(object sender, AdapterView.ItemClickEventArgs e)
    {
        click_Employee = e.Position + 1;
        ICursor c = dbHelper.getSingleEntry(click_Employee);
        c.MoveToFirst();
        name = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_NAME));
        email = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_EMAIL));
        phone = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_PHONE));
        designation = c.GetString(c.GetColumnIndex(dbHelper.EMPLOYEE_DESIGNATION));
        dName.Text = name;
        dEmail.Text = email;
        dPhone.Text = phone;
        dDesignation.Text = designation;
    }


}}

更新3：

波紋管是complete_data和update的xmls

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp">
<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <ListView
            android:id="@+id/listView1"
            android:layout_width="match_parent"
            android:layout_height="350dp"
            android:divider="#000"
            android:dividerHeight="1dp" />
        <TextView
            android:id="@+id/eName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Name" />
        <TextView
            android:id="@+id/eEmail"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Email" />
        <TextView
            android:id="@+id/ePhone"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Phone" />
        <TextView
            android:id="@+id/eDesignation"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Designation" />
    </LinearLayout></ScrollView></LinearLayout>

更新xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp">
<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <ListView
            android:id="@+id/listView1"
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:divider="#000"
            android:dividerHeight="1dp" />
        <EditText
            android:id="@+id/upName"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:hint="Name" />
        <EditText
            android:id="@+id/upEmail"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:hint="Email" />
        <EditText
            android:id="@+id/upPhone"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:hint="Phone" />
        <EditText
            android:id="@+id/upDesignation"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:hint="Designation" />
        <Button
            android:id="@+id/updateEmploy"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Update Employee" />
    </LinearLayout></ScrollView></LinearLayout> 

為了更好地理解，上面給出了示例代碼。

任何幫助將不勝感激

Answer 1

問題是您使用了錯誤的View ID。 在您的XML中有upName ，並且您正在搜索Resource.Id.eName 。
要解決問題，您需要將Resource.Id.eName更改為Resource.Id.upName