Question

我正在尝试跟进并完成YouTube Address Book Tutorial

上的地址簿教程

但是我遇到了一些我不明白的障碍。接下来我找不到代码的区别。所以我认为它必须是我失踪的财产设置。当我测试填充列表时，我可以选择第一个项目。但是当我选择第二项时，调试器会发出错误

无效参数=＆＃39; 0＆＃39;对于＆＃39; index＆＃39;
无效

有人能告诉我为什么会抛出这个错误吗？听视频听起来像代码中的0就是告诉列表你一次只能选择一个项目。不幸的是，我还没有弄清楚为什么他的代码有效，而我的代码却没有。

private void button3_Click(object sender, EventArgs e)
{
    person p = new person(); // creates new string array
    p.Name = textBox1.Text;  // name    
    p.StreetAddress= textBox3.Text; // address
    p.Email = textBox2.Text;  // email
    p.Birthday = dateTimePicker1.Value;  //birthday
    p.AdditionalNotes = textBox4.Text;  // any notes
    people.Add(p); // tells the the above data to be added to the people list.
    listView1.Items.Add(p.Name); // makes its show on the listview of the main box.
    textBox1.Text = "";
    textBox2.Text = "";
    textBox3.Text = "";
    textBox4.Text = "";
    dateTimePicker1.Value = DateTime.Now;

}

private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{

    textBox1.Text = people[listView1.SelectedItems[0].Index].Name; //Debugger points error here.
    textBox2.Text = people[listView1.SelectedItems[0].Index].Email;
    textBox3.Text = people[listView1.SelectedItems[0].Index].StreetAddress;
    textBox4.Text = people[listView1.SelectedItems[0].Index].AdditionalNotes;
    dateTimePicker1.Value = people[listView1.SelectedItems[0].Index].Birthday;
}


class person
{
    public string Name
    {
        get;
        set;
    }  ...
}

Answer 1

我设法与程序创建者交谈。解决方案是检查并处理没有选择。因此，添加If语句解决了问题。

private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (listView1.SelectedItems.Count == 0) return;  // This line added will solve the problem
    textBox1.Text = people[listView1.SelectedItems[0].Index].Name; 
    textBox2.Text = people[listView1.SelectedItems[0].Index].Email;
    textBox3.Text = people[listView1.SelectedItems[0].Index].StreetAddress;
    textBox4.Text = people[listView1.SelectedItems[0].Index].AdditionalNotes;
    dateTimePicker1.Value = people[listView1.SelectedItems[0].Index].Birthday;
}

YouTube教程无法在列表视图中选择第二个项目（无效参数）

1 个答案: