c# Windows窗体-如何在运行时创建新的文本框/侧标签(也在运行时创建)

本文关键字：运行时 创建 标签 文本 窗体 Windows | 更新日期: 2023-09-27 18:12:05

这是可能的，例如:

form start with 1 textbox(name: textbox1) and 1 label(name: label1)在运行时创建文本框和标签(side-side)所以在运行时我们可以输入

label1 - textbox1
label2 - textbox2
label3 - textbox3
label4 - textbox4

在编译可执行文件之前，如何在代码中引用这些未来文本框/标签而不会出现这些文本框/标签不存在的错误?

大家都知道，我是这样在运行时创建新的文本框和标签的

            n++;
            TextBox txt = new TextBox();
            txt.Name = "textbox" + n;
            txt.Text = "";
            txt.Size = new System.Drawing.Size(189, 26);
            txt.Location = new Point(87, n2);
            testelogico = txt.Name;
            gpbCategoria.Controls.Add(txt);
            txt.TextChanged += new EventHandler(new_onchange);
            txt.Leave += new EventHandler(erase_onLeave);
            Label lbl = new Label();
            lbl.Name = "label" + n;
            lbl.Text = "Acessório Nº" + n + ":";
            lbl.Location = new Point(4, n2 + 5);
            gpbCategoria.Controls.Add(lbl);

在代码的另一部分，我想引用例如:

If (textbox4.Text == "" && label4.Name == "Acessório Nº4:")
{
gpbCategoria.Controls.Remove(textbox4);
gpbCategoria.Controls.Remove(label4);
}

但是我会有错误，因为这些标签还不存在(只会在运行时创建)

c# Windows窗体-如何在运行时创建新的文本框/侧标签(也在运行时创建)

您正在动态生成控件，因此编译器在创建textBox4之前不知道它是什么。你所能做的就是在运行时根据控件的名称搜索该控件:

TextBox textbox4 = (TextBox)this.Controls.Find("textbox4", false).FirstOrDefault();
if (textbox4 == null)
{
    throw new Exception("Could not find textbox4.");
}

这将在Form.Controls中搜索textbox4，如果不存在则抛出异常。您可以对labels或任何其他形式的控件遵循相同的模式。

您可以通过名称找到文本框:

var textbox = this.Controls.OfType<TextBox>().Single(ctr => ctr.Name == "textboxname");

在UserControl中放置Label - TextBox比较好。

让UserControl拥有通过构造函数传递的索引号

   public class MyUserControl : UserControl 
   {
      private readonly int index;
      public MyUserControl(int index)
      {
         this.index = index;
         InitializeComponent(); // will init you sub controls: label and textbox
         // set name to label
      } 
      public int Index
      {
         get { return index; }
      } 
   }

使用已经建议的方法通过控件集合中的索引查找您的用户控件，如果找到则删除它。

嗨@programmer93和@Jonesy，感谢帮助，现在它工作得很好，看到我的最终代码(可以帮助有同样疑问的人，我有)

    TextBox txtAcessorio4 = (TextBox)gpbCategoria.Controls.Find("txtAcessorio4", false).FirstOrDefault();
Label lblAcessorio4 = (Label)gpbCategoria.Controls.Find("lblAcessorio4", false).FirstOrDefault();
                    if (txtAcessorio4 != null && txtAcessorio4.Text == "" && lblAcessorio4.Name == "lblAcessorio4")
                    {
                        MessageBox.Show("Perfect");                           
                    }

如果你使用的是。net framework 4.0或更高版本，那么你可以使用动态关键字:下面是完整的代码供您参考:

public class Class1
{
    // Declare all the controls as dynamic
    dynamic textbox1, textbox2, textbox3, textbox4;
    dynamic label1, label2, label3, label4;
    public Class1()
    {
        // Create the actual object type, which they will hold at Run time. 
        textbox1 = textbox2 = textbox3 = textbox4 = new TextBox();
        label1 = label2 = label3 = label4 = new Label();
        // Loop through to create controls at Runtime.
        n++;
        TextBox txt = new TextBox();
        txt.Name = "textbox" + n;
        txt.Text = "";
        txt.Size = new System.Drawing.Size(189, 26);
        txt.Location = new Point(87, n2);
        testelogico = txt.Name;
        gpbCategoria.Controls.Add(txt);
        txt.TextChanged += new EventHandler(new_onchange);
        txt.Leave += new EventHandler(erase_onLeave);
        Label lbl = new Label();
        lbl.Name = "label" + n;
        lbl.Text = "Acessório Nº" + n + ":";
        lbl.Location = new Point(4, n2 + 5);
        gpbCategoria.Controls.Add(lbl);
    }
    public void Foo()
    {
        //Throw exception if controls are not initialized yet.
        if (textbox4 == null || label4 == null)
        {
            throw new Exception("Controls not initialized.");
        }
        else
        {
            // You can access the control propoties similar to normal controls.
            if (textbox4.Text == "" && label4.Name == "Acessório Nº4:")
            {
                gpbCategoria.Controls.Remove(textbox4);
                gpbCategoria.Controls.Remove(label4);
            }
        }
    }
}
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