如何在C＃中更新文本框的值 [英] How to updated the value of a textbox in C#
问题描述
嗨
我正在尝试更新文本框，但它不起作用。
来自< do something =here =>的值应该不加思索地更新到textbox2。
它编译得很好，但文本框永远不会更新！
br
Nikolaj
--------------------------------- -------------------------------------------------- ---
Hi
I'm trying to update a textbox, but it doesn't work.
The value from <do something="" here=""> should immitiately be updated into textbox2.
It compiles fine, but textbox is never updated !
br
Nikolaj
--------------------------------------------------------------------------------------
namespace Excel_form
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
excel.excel_init(textBox1.Text.ToString());
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
}
public delegate void TextBoxDelegate(string message);
public void UpdatingTextBox(string msg)
{
if (textBox2.InvokeRequired)
textBox2.Invoke(new TextBoxDelegate(UpdatingTextBox), new object[] { msg });
else
{
textBox2.Text = msg;
}
}
}
public static class excel
{
public static string excel_getCellValue(string lookFor)
{
do something here (value comes from here) ............
........................
.....................
Form1 fm1 = new Form1();
fm1.UpdatingTextBox(value);
}
}
}
推荐答案
As Wes Aday 建议您在excel_getCellValue方法中错误地创建Form1的新实例。
您必须调用现有Form1的实例。UpdatingTextBox方法
As Wes Aday suggested, you are wrongly creating a new instance ofForm1in yourexcel_getCellValuemethod.
You have to call theUpdatingTextBoxmethod of the existingForm1instance.
：叹息：
看看你的代码：
:sigh:
Look at your code:
Form1 fm1 = new Form1();
fm1.UpdatingTextBox(value);
new 关键字有什么作用？
你知道吗：它会创建该类的 新实例 - 然后您将其更新以反映新值。这不会反映在当前显示中，因为这是与您刚刚创建的表单不同的表单实例。
您需要获取excel类更新实际显示 - 通过提供表单处理和更新的已更改事件来最好地处理。
请参阅此处：在两种形式之间传递信息，第2部分：儿童到父母 [ ^ ] - 将您的表单视为父级，将您的excel类视为子级，它应该解释如何做。
What does the new keyword do?
You know that: it creates a new instance of the class - which you then update to reflect the new value. That won't be reflected in the the current display because that is a different instance of the Form from the one you just created.
You need to get the excel class to update the actual display - which its best handled by providing a "Changed" event which the form handles and updates itself.
See here: Transferring information between two forms, Part 2: Child to Parent[^] - think of your form as the Parent, and your excel class as the Child, and it should explain how to do it.
好的，下面的代码正在运行。这是一个可接受的解决方案（代码实践明智）？
----------------------- --------------------
命名空间Excel_form
{
公共部分类Form1：表格
{
public Form1（）
{
InitializeComponent（）;
}
private void Form1_Load（object sender，EventArgs e）
{
}
private void button1_Click（object sender，EventArgs e）
{
Excel.Excel_init（ this ，textBox1.Text.ToString（））;
}
private void textBox1_TextChanged（object sender，EventArgs e）
{
}
private void textBox2_TextChanged（objec t发件人，EventArgs e）
{
}
public delegate void TextBoxDelegate（string message）;
public void UpdatingTextBox（string msg）
{
if（textBox2.InvokeRequired）
textBox2.Invoke（new TextBoxDelegate（UpdatingTextBox），new object [] {msg}）;
else
{
textBox2.Text = msg;
}
}
}
公共静态类Excel
{
公共静态字符串Excel_getCellValue（ Form1 abc ，字符串lookFor）
{
在这里做点什么（价值来自这里）............
...................... ..
.....................
abc.UpdatingTextBox（value）; //这不起作用
}
< br $>
}
}
Ok, the below code is working. Is that an acceptable solution (code practice wise)?
-------------------------------------------
namespace Excel_form
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
Excel.Excel_init(this, textBox1.Text.ToString());
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
private void textBox2_TextChanged(object sender, EventArgs e)
{
}
public delegate void TextBoxDelegate(string message);
public void UpdatingTextBox(string msg)
{
if (textBox2.InvokeRequired)
textBox2.Invoke(new TextBoxDelegate(UpdatingTextBox), new object[] { msg });
else
{
textBox2.Text = msg;
}
}
}
public static class Excel
{
public static string Excel_getCellValue(Form1 abc, string lookFor)
{
do something here (value comes from here) ............
........................
.....................
abc.UpdatingTextBox(value); // this is not working
}
}
}
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