如何以编程方式复制组合框内容？ [英] How can I copy combobox contents programmatically?

问题描述

我有这个代码：

  private void FormMain_Shown（object sender，EventArgs e）
 {
 ComboBox cmbx; 
 foreach（Control.C in this.Controls）
 {
 if（C.GetType（）== typeof（ComboBox））
 {
 cmbx = C as ComboBox ; 
 //cmbx.Items.AddRange(cmbxRow0Element0.Items）; < = illegal 
 object [] obj = new object [cmbxRow0Element0.Items.Count]; 
 cmbxRow0Element0.Items.CopyTo（obj，0）; 
 cmbx.Items.AddRange（obj）; 
} 
} 
} 
  

...工作 - 我有一个tabPage上的几个组合框在表单上的tabControl，cmbxRow0Element0填充项目在设计时。上述尝试将其项目复制到所有其他组合框失败了。

UPDATE

代码我现在有，它仍然不工作：

  public FormMain（）
 {
 InitializeComponent（）; 
 
 for（int i = 0; i <10; i ++）
 {
 this.cmbxRow0Element0.Items.Add（String.Format（Item {0} i.ToString（）））; 
} 
 foreach（Control.C in this.Controls）
 {
 ComboBox cmbx = null; 
 
 //&测试确保我们不只是找到源组合框
 if（（C.GetType（）== typeof（ComboBox））&（（C as ComboBox）！= this.cmbxRow0Element0））
 cmbx = C as ComboBox; 
 if（cmbx！= null）
 {
 foreach（cmbxRow0Element0.Items中的对象项）
 {
 cmbx.Items.Add（item）; 
} 
} 
 
} 
} 
  

UPDATE 2

p>到达第一行的断点，但第二行未到达：

  if（（C.GetType （）== typeof（ComboBox））&（（C as ComboBox）！= this.cmbxRow0Element0））
 cmbx = C as ComboBox; 
  

UPDATE 3

问题是find不够具体 - 必须指定特定的tabPage。有关详情，请参见此 。

解决方案

快速测试Windows窗体应用程序（VS Express 2012）显示了这一工作。在新的空白Windows窗体应用程序中，删除三个（或更多）ComboBox控件：

  public Form1（）
 { 
 InitializeComponent（）; 
 for（int i = 0; i <10; i ++）
 {
 this.comboBox1.Items.Add（String.Format（Item {0}，i.ToString ）））; 
} 
 foreach（Control.C in this.Controls）
 {
 ComboBox cmbx = null; 
 
 //&测试确保我们不只是找到源组合框
 if（（C.GetType（）== typeof（ComboBox））&（（C as ComboBox）！= this.comboBox1））
 cmbx = C as ComboBox; 
 if（cmbx！= null）
 {
 foreach（comboBox1.Items中的对象项）
 {
 cmbx.Items.Add（item）; 
} 
} 
 
} 
} 
  

I've got this code:

private void FormMain_Shown(object sender, EventArgs e)
{
    ComboBox cmbx;
    foreach (Control C in this.Controls)
    {
        if (C.GetType() == typeof(ComboBox))
        {
            cmbx = C as ComboBox;
            //cmbx.Items.AddRange(cmbxRow0Element0.Items); <= illegal
            object[] obj = new object[cmbxRow0Element0.Items.Count];
            cmbxRow0Element0.Items.CopyTo(obj, 0);
            cmbx.Items.AddRange(obj);
        }
    }
}

...but it doesn't work - I have several combo boxes on a tabPage on a tabControl on a Form, with cmbxRow0Element0 populated with items at design time. The above attempt to copy its items to all the other comboboxes fails, though.

UPDATE

This is the code I now have, and it still doesn't work:

public FormMain()
{
    InitializeComponent();

    for (int i = 0; i < 10; i++)
    {
        this.cmbxRow0Element0.Items.Add(String.Format("Item {0}", i.ToString()));
    }
    foreach (Control C in this.Controls)
    {
        ComboBox cmbx = null;

        // The & test ensures we're not just finding the source combobox
        if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.cmbxRow0Element0))
            cmbx = C as ComboBox;
        if (cmbx != null)
        {
            foreach (Object item in cmbxRow0Element0.Items)
            {
                cmbx.Items.Add(item);
            }
        }

    }
}

Perhaps it's something to do with the comboboxes being on tab pages on the tab control?

UPDATE 2

A breakpoint on the first line below is reached, but the second line is never reached:

if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.cmbxRow0Element0))
   cmbx = C as ComboBox;

UPDATE 3

The problem was the "find" was not being specific enough - the particular tabPage has to be specified. For more details, see this.

解决方案

A quick test Windows Form app (VS Express 2012) shows this works. In a new blank Windows Form app, drop three (or more) ComboBox controls:

    public Form1()
    {
        InitializeComponent();
        for (int i = 0; i < 10; i++)
        {
            this.comboBox1.Items.Add(String.Format("Item {0}", i.ToString()));
        }
        foreach (Control C in this.Controls)
        {
            ComboBox cmbx = null;

            // The & test ensures we're not just finding the source combobox
            if ((C.GetType() == typeof(ComboBox)) & ((C as ComboBox) != this.comboBox1))
                cmbx = C as ComboBox;
            if (cmbx != null)
            {
                foreach (Object item in comboBox1.Items)
                {
                    cmbx.Items.Add(item);
                }
            }

        }
    }

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