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如何在ListBox中将项目上下移动？

c#.netwinformslistbox
37
我有一个listBox1对象，其中包含一些项目。我有一个按钮可以将选定的项目向上移动，另一个按钮可以将选定的项目向下移动。这两个按钮的代码应该是什么？
你是考虑客户端还是服务器端？ - Hawxby
WinForms，WPF，ASP.NET？ - Jay
15个回答
91
 public void MoveUp()
 {
     MoveItem(-1);
 }

 public void MoveDown()
 {
    MoveItem(1);
 }

 public void MoveItem(int direction)
 {
    // Checking selected item
    if (listBox1.SelectedItem == null || listBox1.SelectedIndex < 0)
        return; // No selected item - nothing to do

    // Calculate new index using move direction
    int newIndex = listBox1.SelectedIndex + direction;

    // Checking bounds of the range
    if (newIndex < 0 || newIndex >= listBox1.Items.Count)
        return; // Index out of range - nothing to do

    object selected = listBox1.SelectedItem;

    // Removing removable element
    listBox1.Items.Remove(selected);
    // Insert it in new position
    listBox1.Items.Insert(newIndex, selected);
    // Restore selection
    listBox1.SetSelected(newIndex, true);
}

更新于2020-03-24: 扩展类可简单重用，同时还支持CheckedListBox（如果您不需要CheckedListBox，请删除相应的代码行）。感谢@dognose和@Chad

public static class ListBoxExtension
{
    public static void MoveSelectedItemUp(this ListBox listBox)
    {
        _MoveSelectedItem(listBox, -1);
    }

    public static void MoveSelectedItemDown(this ListBox listBox)
    {
        _MoveSelectedItem(listBox, 1);
    }

    static void _MoveSelectedItem(ListBox listBox, int direction)
    {
        // Checking selected item
        if (listBox.SelectedItem == null || listBox.SelectedIndex < 0)
            return; // No selected item - nothing to do

        // Calculate new index using move direction
        int newIndex = listBox.SelectedIndex + direction;

        // Checking bounds of the range
        if (newIndex < 0 || newIndex >= listBox.Items.Count)
            return; // Index out of range - nothing to do

        object selected = listBox.SelectedItem;

        // Save checked state if it is applicable
        var checkedListBox = listBox as CheckedListBox;
        var checkState = CheckState.Unchecked;
        if (checkedListBox != null)
            checkState = checkedListBox.GetItemCheckState(checkedListBox.SelectedIndex);

        // Removing removable element
        listBox.Items.Remove(selected);
        // Insert it in new position
        listBox.Items.Insert(newIndex, selected);
        // Restore selection
        listBox.SetSelected(newIndex, true);

        // Restore checked state if it is applicable
        if (checkedListBox != null)
            checkedListBox.SetItemCheckState(newIndex, checkState);
    }
}
3
这段代码的抽象程度比被接受的答案更好。我在我的代码中做的一个额外的事情是添加了一个 ListBox 参数，因此只需将其传递给函数即可在任何 ListBox 上使用该函数。 - Chad
1
如果这是一个ChckedListBox，您可能还想添加以下两行代码：在移动之前添加 CheckState checkState = checkedListBox1.GetItemCheckState(checkedListBox1.SelectedIndex);，并在末尾添加以下一行代码：checkedListBox1.SetItemCheckState(newIndex, checkState); - dognose
19
private void UpClick()
{
    // only if the first item isn't the current one
    if(listBox1.ListIndex > 0)
    {
        // add a duplicate item up in the listbox
        listBox1.AddItem(listBox1.Text, listBox1.ListIndex - 1);
        // make it the current item
        listBox1.ListIndex = (listBox1.ListIndex - 2);
        // delete the old occurrence of this item
        listBox1.RemoveItem(listBox1.ListIndex + 2);
    }
}

private void DownClick()
{
   // only if the last item isn't the current one
   if((listBox1.ListIndex != -1) && (listBox1.ListIndex < listBox1.ListCount - 1))
   {
      // add a duplicate item down in the listbox
      listBox1.AddItem(listBox1.Text, listBox1.ListIndex + 2);
      // make it the current item
      listBox1.ListIndex = listBox1.ListIndex + 2;
      // delete the old occurrence of this item
      listBox1.RemoveItem(listBox1.ListIndex - 2);
   }
}
4
ListIndex 对我没有起作用。我使用了 Save 的答案。 - IanK.CO
'ListBox' 对象没有 'ListIndex' 属性。 - Dmitry Dronov
7
你有没有尝试在谷歌上搜索？例如，移动ListBox控件中的项目。
public class SmartListBox : ListBox
{
    //Moves the selected items up one level
    public MoveUp()
    {

        for(int i = 0; i < Items.Count; i++)
        {
            if (Items[i].Selected)//identify the selected item
            {
                //swap with the top item(move up)
                if (i > 0 && !Items[i - 1].Selected)
                {
                     ListItem bottom = Items[i];
                     Items.Remove(bottom);
                     Items.Insert(i - 1, bottom);
                     Items[i - 1].Selected = true;
                 }
              }
          }
     }
     //Moves the selected items one level down
     public MoveDown()
     {
         int startindex = Items.Count -1;
         for (int i = startindex; i > -1; i--)
         {
              if (Items[i].Selected)//identify the selected item
              { 
                  //swap with the lower item(move down)
                  if (i < startindex && !Items[i + 1].Selected)
                  {
                       ListItem bottom = Items[i];
                       Items.Remove(bottom);
                       Items.Insert(i + 1, bottom);
                       Items[i + 1].Selected = true;
                  }

              }
         }
     }
}
3
你的方法中返回类型在哪里？ - user586399
5

修改了@Save代码，以允许使用DataSource属性将数据绑定到ListBox的项进行移动。

public void MoveItem(int direction)
        {
            // Checking selected item
            if (listBox1.SelectedItem == null || listBox1.SelectedIndex < 0)
                return; // No selected item - nothing to do

            // Calculate new index using move direction
            int newIndex = listBox1.SelectedIndex + direction;

            // Checking bounds of the range
            if (newIndex < 0 || newIndex >= listBox1.Items.Count)
                return; // Index out of range - nothing to do

            UnifyCamera selected = listBox1.SelectedItem as UnifyCamera;

            // modify the data source list
            inputData.Cameras.RemoveAt(listBox1.SelectedIndex);
            inputData.Cameras.Insert(newIndex, selected);

            // re-bind your data source
            ((ListBox)listBox1).DataSource = null;
            ((ListBox)listBox1).DataSource = this.inputData.Cameras;
            ((ListBox)listBox1).DisplayMember = "Name";

            // Restore selection
            listBox1.SetSelected(newIndex, true);
        }

这里的UnifyCamera是我的自定义类，存储在列表inputData.Cameras中，该列表返回一个List<UnifyCamera>。

4

将上述修改后的荒芜者代码作为参数传递控制...可重复使用

    private void MoveUp()
    {
        MoveItem(-1,listBox1);
    }      


    private void MoveDown()
    {
        MoveItem(1,listBox1);
    }

    public void MoveItem(int direction,ListBox listBox)
    {
        // Checking selected item
        if (listBox.SelectedItem == null || listBox.SelectedIndex < 0)
            return; // No selected item - nothing to do

        // Calculate new index using move direction
        int newIndex = listBox.SelectedIndex + direction;

        // Checking bounds of the range
        if (newIndex < 0 || newIndex >= listBox.Items.Count)
            return; // Index out of range - nothing to do

        object selected = listBox.SelectedItem;

        // Removing removable element
        listBox.Items.Remove(selected);
        // Insert it in new position
        listBox.Items.Insert(newIndex, selected);
        // Restore selection
        listBox.SetSelected(newIndex, true);
    }
2

Vexe的回答对我来说运行得最好，但是我不得不修改它来解决一些问题。该解决方案将在列表框中多次出现相同对象时突出显示正确的对象。此外，该解决方案防止多选对象在击中列表框的顶部或底部并且按钮被多次按下时翻转。

    private void btnMoveUp_Click(object sender, EventArgs e)
    {
        // find the lowest index of non selected items
        int lowestIndexNotSelected = listBox.Items.Count - 1;
        for (int i = listBox.Items.Count - 1; i >= 0; i--)
        {
            if (!listBox.SelectedIndices.Contains(i))
            {
                lowestIndexNotSelected = i;
            }
        }

        listBox.BeginUpdate();
        int numberOfSelectedItems = listBox.SelectedItems.Count;
        for (int i = 0; i < numberOfSelectedItems; i++)
        {
            // only if it's not a lower inde than the lowest non selected index
            if (listBox.SelectedIndices[i] > lowestIndexNotSelected)
            {
                // the index of the item above the item that we wanna move up
                int indexToInsertIn = listBox.SelectedIndices[i] - 1;
                // insert UP the item that we want to move up
                listBox.Items.Insert(indexToInsertIn, listBox.SelectedItems[i]);
                // removing it from its old place
                listBox.Items.RemoveAt(indexToInsertIn + 2);
                // highlighting it in its new place (by index, to prevent highlighting wrong instance)
                listBox.SelectedIndex = indexToInsertIn;
            }
        }
        listBox.EndUpdate();
    }

    private void btnMoveDown_Click(object sender, EventArgs e)
    {
        // find the highest index of non selected items
        int highestIndexNonSelected = 0;
        for (int i = 0; i < listBox.Items.Count; i++)
        {
            if (!listBox.SelectedIndices.Contains(i))
            {
                highestIndexNonSelected = i;
            }
        }

        listBox.BeginUpdate();
        int numberOfSelectedItems = listBox.SelectedItems.Count;
        // when going down, instead of moving through the selected items from top to bottom
        // we'll go from bottom to top, it's easier to handle this way.
        for (int i = numberOfSelectedItems - 1; i >= 0; i--)
        {
            // only if it's not a higher index than the highest index not selected
            if (listBox.SelectedIndices[i] < highestIndexNonSelected)
            {
                // the index of the item that is currently below the selected item
                int indexToInsertIn = listBox.SelectedIndices[i] + 2;
                // insert DOWN the item that we want to move down
                listBox.Items.Insert(indexToInsertIn, listBox.SelectedItems[i]);
                // removing it from its old place
                listBox.Items.RemoveAt(indexToInsertIn - 2);
                // highlighting it in its new place (by index, to prevent highlighting wrong instance)
                listBox.SelectedIndex = indexToInsertIn - 1;
            }
        }
        listBox.EndUpdate();
    }
2
public static void MoveUpOrDownSelectedItem(ListBox LisBox, bool MoveUp)
 {
          if (LisBox.SelectedIndex > 0 && MoveUp)
          {
             // add a duplicate item up in the listbox
             LisBox.Items.Insert(LisBox.SelectedIndex - 1, LisBox.SelectedItem);
             // make it the current item
             LisBox.SelectedIndex = (LisBox.SelectedIndex - 2);
             // delete the old occurrence of this item
              LisBox.Items.RemoveAt(LisBox.SelectedIndex + 2);
          }
        if ((LisBox.SelectedIndex != -1) && (LisBox.SelectedIndex < LisBox.Items.Count- 1) && MoveUp == false)     
        {
            // add a duplicate item down in the listbox
            int IndexToRemove = LisBox.SelectedIndex;
            LisBox.Items.Insert(LisBox.SelectedIndex + 2, LisBox.SelectedItem);
            // make it the current item
            LisBox.SelectedIndex = (LisBox.SelectedIndex + 2);
            // delete the old occurrence of this item
            LisBox.Items.RemoveAt(IndexToRemove);
        }
    }
2
所有其他答案都不错，但你也应该考虑这个：） 它的想法与SwDevMan81的类似，但这是真正的代码（不是伪代码）， 而且你可以移动多个项目（选择多个项目） 并且在向下移动时还有一个改进。
private void MoveUp_listBox_button_Click(object sender, EventArgs e)
{
  listBox.BeginUpdate();
  int numberOfSelectedItems = listBox.SelectedItems.Count;
  for (int i = 0; i < numberOfSelectedItems; i++)
  {
    // only if it's not the first item
    if (listBox.SelectedIndices[i] > 0)
    {
      // the index of the item above the item that we wanna move up
      int indexToInsertIn = listBox.SelectedIndices[i] - 1;
      // insert UP the item that we want to move up
      listBox.Items.Insert(indexToInsertIn, listBox.SelectedItems[i]);
      // removing it from its old place
      listBox.Items.RemoveAt(indexToInsertIn + 2);
      // highlighting it in its new place
      listBox.SelectedItem = listBox.Items[indexToInsertIn];
    }
  }
  listBox.EndUpdate();
}

private void MoveDown_listBox_button_Click(object sender, EventArgs e)
{
  listBox.BeginUpdate();
  int numberOfSelectedItems = listBox.SelectedItems.Count;
  // when going down, instead of moving through the selected items from top to bottom
  // we'll go from bottom to top, it's easier to handle this way.
  for (int i = numberOfSelectedItems-1; i >= 0; i--)
  {
    // only if it's not the last item
    if (listBox.SelectedIndices[i] < listBox.Items.Count - 1)
    {
      // the index of the item that is currently below the selected item
      int indexToInsertIn = listBox.SelectedIndices[i] + 2;
      // insert DOWN the item that we want to move down
      listBox.Items.Insert(indexToInsertIn, listBox.SelectedItems[i]);
      // removing it from its old place
      listBox.Items.RemoveAt(indexToInsertIn - 2);
      // highlighting it in its new place
      listBox.SelectedItem = listBox.Items[indexToInsertIn - 1];
    }
  }
  listBox.EndUpdate();
}
1
获取所选项目的集合，然后按如下方式移动它们：
private void btnMoveUp_Click(object sender, EventArgs e)
{
  HashSet<KeyValuePair<int, object>> ItemsToMove = new HashSet<KeyValuePair<int, object>>();

  foreach (object o in lstMyListView.SelectedItems)
    ItemsToMove.Add(new KeyValuePair<int, object>(lstMyListView.Items.IndexOf(o), o));

  foreach (KeyValuePair<int, object> kvp in ItemsToMove)
  {
    if (kvp.Key > 0) // check if its the first item before moving
    {
      lstMyListView.Items.Remove(kvp.Value);
      lstMyListView.Items.Insert(kvp.Key - 1, kvp.Value);
    }
  }
}

private void btnMoveDown_Click(object sender, EventArgs e)
{
  HashSet<KeyValuePair<int, object>> ItemsToMove = new HashSet<KeyValuePair<int, object>>();

  foreach (object o in lstMyListView.SelectedItems)
    ItemsToMove.Add(new KeyValuePair<int, object>(lstMyListView.Items.IndexOf(o), o));

  foreach (KeyValuePair<int, object> kvp in ItemsToMove)
  {
    if (kvp.Key < lstMyListView.Items.Count - 1) // check if its the last item before moving
    {
      lstMyListView.Items.Remove(kvp.Value);
      lstMyListView.Items.Insert(kvp.Key + 1, kvp.Value);
    }
  }
}
1

对于那些正在寻找一种通用的方法来处理ListBox，该方法可以绑定到数据源，这里提供了一个基于Save's answer的通用扩展程序，可以处理常规和绑定的ListBox。

public static void MoveUp(this ListBox listBox)
{
    listBox.MoveItem(-1);
}

public static void MoveDown(this ListBox listBox)
{
    listBox.MoveItem(1);
}

public static void MoveItem(this ListBox listBox, int direction)
{
    // Checking selected item
    if (listBox.SelectedItem == null || listBox.SelectedIndex < 0)
        return; // No selected item - nothing to do

    // Calculate new index using move direction
    int newIndex = listBox.SelectedIndex + direction;

    // Checking bounds of the range
    if (newIndex < 0 || newIndex >= listBox.Items.Count)
        return; // Index out of range - nothing to do


    //Find our if we're dealing with a BindingSource
    bool isBindingSource = listBox.DataSource is BindingSource;

    //Get the list
    System.Collections.IList list = isBindingSource ? ((BindingSource)listBox.DataSource).List : listBox.Items;

    object selected = listBox.SelectedItem;

    // Removing removable element
    list.Remove(selected);

    // Insert it in new position
    list.Insert(newIndex, selected);

    // Restore selection
    listBox.SetSelected(newIndex, true);

    if (isBindingSource)
    {
        //Reset the binding if needed
        ((BindingSource)listBox.DataSource).ResetBindings(false);
    }

}
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