C# WPF如何动态创建文本框并在单击按钮时找到文本框？

WPF how do I create a textbox dynamically and find the textbox on a button click?

提问by David Basarab

I am creating a TextBoxand a Buttondynamically using the following code:

我正在使用以下代码动态创建 aTextBox和 a Button：

Button btnClickMe = new Button();
btnClickMe.Content = "Click Me";
btnClickMe.Name = "btnClickMe";
btnClickMe.Click += new RoutedEventHandler(this.CallMeClick);

someStackPanel.Childern.Add(btnClickMe);

TextBox txtNumber = new TextBox();
txtNumber.Name = "txtNumber";
txtNumber.Text = "1776";

someStackPanel.Childern.Add(txtNumber);

I hook up to a click event to the Click Mebutton. The click me button even is fired correctly. However I cannot find the TextBoxI entered dynamically.

我将点击事件连接到Click Me按钮。单击我按钮甚至被正确触发。但是我找不到TextBox我动态输入的。

Here is my click me event:

这是我的点击我事件：

protected void ClickMeClick(object sender, RoutedEventArgs e)
{
    // Find the phone number
    TextBox txtNumber = this.someStackPanel.FindName("txtNumber") as TextBox;

    if (txtNumber != null)
    {
        string message = string.Format("The number is {0}", txtNumber.Text);

        MessageBox.Show(message);    
    }
    else
    {
        MessageBox.Show("Textbox is null");
    }
}

How can I find the TextBoxtxtNumber?

我怎样才能找到TextBoxtxtNumber？

采纳答案by hughdbrown

Josh G had the clue that fixed this code: use RegisterName().

Josh G 有修复此代码的线索：使用 RegisterName()。

Three benefits here:

这里的三个好处：

1. Doesn't use a member variable to save the reference to the dynamically created TextBox.
2. Compiles.

3. Complete code.

   using System;
   using System.Windows;
   using System.Windows.Controls;
   
   namespace AddControlsDynamically
   {
       public partial class Window1 : Window
       {
           public void Window_Loaded(object sender, RoutedEventArgs e)
           {
               GenerateControls();
           }
           public void GenerateControls()
           {
               Button btnClickMe = new Button();
               btnClickMe.Content = "Click Me";
               btnClickMe.Name = "btnClickMe";
               btnClickMe.Click += new RoutedEventHandler(this.CallMeClick);
               someStackPanel.Children.Add(btnClickMe);
               TextBox txtNumber = new TextBox();
               txtNumber.Name = "txtNumber";
               txtNumber.Text = "1776";
               someStackPanel.Children.Add(txtNumber);
               someStackPanel.RegisterName(txtNumber.Name, txtNumber);
           }
           protected void CallMeClick(object sender, RoutedEventArgs e)
           {
               TextBox txtNumber = (TextBox) this.someStackPanel.FindName("txtNumber");
               string message = string.Format("The number is {0}", txtNumber.Text);
               MessageBox.Show(message);
           }
       }
   }
   

1. 不使用成员变量来保存对动态创建的 TextBox 的引用。
2. 编译。

3. 完整的代码。

   using System;
   using System.Windows;
   using System.Windows.Controls;
   
   namespace AddControlsDynamically
   {
       public partial class Window1 : Window
       {
           public void Window_Loaded(object sender, RoutedEventArgs e)
           {
               GenerateControls();
           }
           public void GenerateControls()
           {
               Button btnClickMe = new Button();
               btnClickMe.Content = "Click Me";
               btnClickMe.Name = "btnClickMe";
               btnClickMe.Click += new RoutedEventHandler(this.CallMeClick);
               someStackPanel.Children.Add(btnClickMe);
               TextBox txtNumber = new TextBox();
               txtNumber.Name = "txtNumber";
               txtNumber.Text = "1776";
               someStackPanel.Children.Add(txtNumber);
               someStackPanel.RegisterName(txtNumber.Name, txtNumber);
           }
           protected void CallMeClick(object sender, RoutedEventArgs e)
           {
               TextBox txtNumber = (TextBox) this.someStackPanel.FindName("txtNumber");
               string message = string.Format("The number is {0}", txtNumber.Text);
               MessageBox.Show(message);
           }
       }
   }
   

回答by bendewey

Is there any way you can make the TextBox control a field in your class instead of a variable inside your generator method

有什么方法可以让 TextBox 控制类中的一个字段而不是生成器方法中的变量

public class MyWindow : Window
{
    private TextBox txtNumber;

    public void Window_Loaded()
    {
        GenerateControls();
    }

    public void GenerateControls()
    {
        Button btnClickMe = new Button();
        btnClickMe.Content = "Click Me";
        btnClickMe.Name = "btnClickMe";
        btnClickMe.Click += new RoutedEventHandler(this.CallMeClick);
        someStackPanel.Childern.Add(btnClickMe);
        txtNumber = new TextBox();
        txtNumber.Name = "txtNumber";
        txtNumber.Text = "1776";
        someStackPanel.Childern.Add(txtNumber);
    }

    protected void ClickMeClick(object sender, RoutedEventArgs e)
    {    
        // Find the phone number    
        string message = string.Format("The number is {0}", txtNumber.Text);        
        MessageBox.Show(message);
    }
}

回答by Micha?l Carpentier

Another method is to set the associated TextBoxas Button Tagwhen instanciating them.

另一种方法是，设置相关联的TextBox作为Button Taginstanciating时它们。

btnClickMe.Tag = txtNumber;

This way you can retrieve it back in event handler.

这样您就可以在事件处理程序中检索它。

protected void ClickMeClick(object sender, RoutedEventArgs e)
{
    Button btnClickMe = sender as Button;
    if (btnClickMe != null)
    {
        TextBox txtNumber = btnClickMe.Tag as TextBox;
        // ...
    }
}

回答by Josh G

If you want to do a comprehensive search through the visual tree of controls, you can use the VisualTreeHelper class.

如果要通过控件的可视化树进行全面搜索，可以使用 VisualTreeHelper 类。

Use the following code to iterate through all of the visual children of a control:

使用以下代码遍历控件的所有可视子项：

for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parentObj); i++)
{
    DependencyObject child = VisualTreeHelper.GetChild(parent, i);

    if (child is TextBox)
        // Do something
}

If you want to search down into the tree, you will want to perform this loop recursively, like so:

如果要向下搜索树，则需要递归地执行此循环，如下所示：

public delegate void TextBoxOperation(TextBox box);

public bool SearchChildren(DependencyObject parent, TextBoxOperation op)
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
    {
        DependencyObject child = VisualTreeHelper.GetChild(parent, i);

        TextBox box = child as TextBox;

        if (box != null)
        {
            op.Invoke(box);
            return true;
        }

        bool found = SearchChildren(child, op);

        if (found)
            return true;
    }
}

回答by Josh G

You can get your original click handler to work by registering the name of the text box:

您可以通过注册文本框的名称来使原始点击处理程序工作：

someStackPanel.RegisterName(txtNumber.Name, txtNumber);

This will then allow you to call FindName on the StackPanel and find the TextBox.

这将允许您在 StackPanel 上调用 FindName 并找到 TextBox。