Question

如果我按下Button1，则表格2->'Hello'中的textBox1

如果我再按一次button2以显示form2，则“ Hello”一词消失，原始Textbox1的文本也会出现。

如何防止按button1的结果消失？

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    } 

    private void Form1_Load(object sender, EventArgs e)
    {

    } 

    private void Button1_Click(object sender, EventArgs e)
    {
        Form2 frm2 = new Form2(this);
        frm2.textBox1.Text = "Hello";
        frm2.Show();
    } 

    private void Button2_Click(object sender, EventArgs e)
    {
        Form2 frm2 = new Form2(this);
        frm2.Show();
    }
}

public partial class Form2 : Form
{
    Form1 frm1 = new Form1();

    public Form2(Form1 _form)
    {
        InitializeComponent();
        frm1 = _form;
    }

    public Form2()
    {
        InitializeComponent();
    } 

    private void Form2_Load(object sender, EventArgs e)
    { 

    }
}

Answer 1

尝试在按钮单击事件之外创建Form2实例。

Answer 2

如果要保留先前在Form2中设置的文本，则不允许关闭Form2。为防止Form2关闭，请在e.Cancel = true;事件处理程序中设置FormClosing：

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }

    private void Form2_FormClosing(object sender, FormClosingEventArgs e)
    {
        e.Cancel = true; // Clancel closing
        Visible = false; // Instead, make Form2 invisible.
    }
}

确保在表单设计器中创建事件处理程序。单独复制/粘贴将无法接通事件。

Form1的代码：

public partial class Form1 : Form
{
    private Form2 _frm2 = new Form2();

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        _frm2.textBox1.Text = "Hello";
        _frm2.Show();
    }

    private void button2_Click(object sender, EventArgs e)
    {
        _frm2.Show();
    }
}

但是可能我们看错了方向。我们不应该使用文本框来存储数据。相反，我们为此目的创建一个数据类。现在，我们可以自由地打开和关闭表格。剩下的只是数据。

public class Data
{
    public string Greeting { get; set; }
}

Form2代码：

private readonly Data _data;

public Form2(Data data) // Note that now, we pass a Data object, not a Form
{
    InitializeComponent();
    _data = data;
    textBox1.Text = _data.Greeting;
}

private void TextBox1_TextChanged(object sender, EventArgs e)
{
    _data.Greeting = textBox1.Text; // Stores back text box edits to the Data object.
}

Form1代码：

private readonly Data _data = new Data();

public Form1()
{
    InitializeComponent();
}

private void Button1_Click(object sender, EventArgs e)
{
    _data.Greeting = "Hello";
    var frm2 = new Form2(_data);
    frm2.Show();
}

private void Button2_Click(object sender, EventArgs e)
{
    var frm2 = new Form2(_data);
    frm2.Show();
}

在2个表格之间我该怎么办？

2 个答案: