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Как переместить элемент в списке вверх и вниз?

У меня есть объект listBox1, и он содержит некоторые элементы. У меня есть кнопка для перемещения выбранного элемента вверх, а другая - для перемещения выбранного элемента вниз. Каким должен быть код для двух кнопок?

25
user586399
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);
   }
}
17
SwDevMan81
 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);
}
67
Save

Вы пытались найти его в Google? Переместить элементы вверх/вниз в списке управления например.

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;
                  }

              }
         }
     }
}
6
CD..

Модифицированный код @Save, позволяющий перемещать элементы, данные которых связаны с ListBox, используя свойство DataSource.

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);
        }

Где UnifyCamera - мой пользовательский класс, который хранится в списке inputData.Cameras, который возвращает List<UnifyCamera>

4
konrad

Модифицированный код Desolator выше, чтобы передать управление в качестве параметра ... многоразового использования

    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);
    }
4
Habesha

Ответ Vexe работал лучше для меня, но мне пришлось изменить его, чтобы исправить пару проблем. Это решение выделит правильный объект, если один и тот же объект находится в списке несколько раз. Кроме того, это решение предотвращает переворот нескольких выбранных объектов, когда они попадают в верхнюю или нижнюю часть списка, а кнопка продолжает нажиматься несколько раз.

    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
Miebster

Все остальные ответы хороши, но вы также должны рассмотреть этот вопрос:) Идея его близка к идее SwDevMan81, но это реальный код (не псевдо) И вы можете переместить более одного элемента (несколько выбранных предметов) и с улучшением при движении вниз.

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();
}
2
vexe
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
Mnyikka
// Options is a list box

private void MoveUpButton_Click(object sender,EventArgs e) {                            
    int index = Options.SelectedIndex;                                          
    if (index <= 0) return;
    string item = (string)Options.Items[index - 1];                         
    Options.Items.RemoveAt(index - 1);                                                                              
    Options.Items.Insert(index,item);                                           
    selectedIndexChanged(null,null);                                                                        
    }

private void MoveDnButton_Click(object sender,EventArgs e) {                            
    int index = Options.SelectedIndex;
    if (index + 1 >= Options.Items.Count) return;
    string item = (string)Options.Items[index];
    Options.Items.RemoveAt(index);
    Options.Items.Insert(index + 1,item);
    Options.SelectedIndex = index + 1;
    }

// sent when user makes a selection or when he moves an item up or down

private void selectedIndexChanged(object sender,EventArgs e) {
    int index = Selected.SelectedIndex;
    MoveUpButton.Enabled = index > 0;
    MoveDnButton.Enabled = index + 1 < Selected.Items.Count;
    }
1
SaulN
private void btnUp_Click(object sender, System.EventArgs e)
{
    if (this.lbItems.SelectedIndex == -1 || this.lbItems.SelectedIndex == 0)
        return;

        Object select, previous, temp;
        select = lbItems.Items[lbItems.SelectedIndex];
        previous = lbItems.Items[lbItems.SelectedIndex-1];
        temp = select;
        select = previous;
        previous = temp;

        lbItems.Items[lbItems.SelectedIndex] = select;
        lbItems.Items[lbItems.SelectedIndex-1] = previous;

        lbItems.SelectedIndex--;            
}

private void btnDown_Click(object sender, System.EventArgs e)
{
    if (this.lbItems.SelectedIndex == -1 || this.lbItems.SelectedIndex == lbItems.Items.Count-1)
        return;     

    Object select, next, temp;
    select = lbItems.Items[lbItems.SelectedIndex];
    next = lbItems.Items[lbItems.SelectedIndex+1];
    temp = select;
    select = next;
    next = temp;

    lbItems.Items[lbItems.SelectedIndex] = select;
    lbItems.Items[lbItems.SelectedIndex+1] = next;
    lbItems.SelectedIndex++;
}
1
harsha

Я использую это с множественными выборами . Это также работает с чередованными выборами.

        private void Order_buttons_Click(object sender, EventArgs e)
    {
        //If noselection return
        if (Layouts_listBox.SelectedItems.Count == 0) return;

        //Determines wether up or down
        int movement = (sender as Button) == Order_Upbutton? - 1 : 1;

        //creates a dictionary associating the original Index (ListBox) to the text
        Dictionary<int, string> Items = new Dictionary<int, string>();

        //Also creates a list with the Index for sorting
        List<int> DesiredOrder = new List<int>();

        //Cycle through the selection and fill both the list and dictionary
        ListBox.SelectedObjectCollection NN = Layouts_listBox.SelectedItems;
        foreach (object n in NN)
        {
            DesiredOrder.Add(Layouts_listBox.Items.IndexOf(n));
            Items.Add(Layouts_listBox.Items.IndexOf(n), (string)n);
        }

        //Sort the List according to the desired button (Up or Down)
        DesiredOrder.Sort();
        if ((sender as Button) != Order_Upbutton) DesiredOrder.Reverse();

        //I'm using this ErrorHandling but thats up to you
        try
        {
            //Call the MoveItem (Credits to Save) according to the sorted order
            foreach (int n in DesiredOrder) MoveItem(movement, Items[n]);
        }
        catch (Exception)
        {
            SystemSounds.Asterisk.Play();
        }
    }
    public void MoveItem(int direction, string Selected)
    {
        // Checking selected item
        if (!Layouts_listBox.Items.Contains(Selected) || Layouts_listBox.Items.IndexOf(Selected) < 0)
            throw new System.Exception(); // No selected item - Cancel entire Func

        // Calculate new index using move direction
        int newIndex = Layouts_listBox.Items.IndexOf(Selected) + direction;

        // Checking bounds of the range
        if (newIndex < 0 || newIndex >= Layouts_listBox.Items.Count)
            throw new System.Exception(); // Index out of range - Cancel entire Func

        object selected = Layouts_listBox.Items[Layouts_listBox.Items.IndexOf(Selected)];

        // Removing removable element
        Layouts_listBox.Items.Remove(selected);
        // Insert it in new position
        Layouts_listBox.Items.Insert(newIndex, selected);
        // Restore selection
        Layouts_listBox.SetSelected(newIndex, true);
    }
0
Marcos Paulo Galinari Chaves

Получите коллекцию выбранных элементов, а затем переместите их следующим образом:

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);
    }
  }
}
0
RooiWillie

Для кнопки вверх: 

  private void UpBottom_Click(object sender, EventArgs e)
    {
        //this.Options is ListBox
        if (this.Options.SelectedIndex == -1 ||
             this.Options.SelectedIndex == 0)
            return;

        string item, aboveItem;
        int itemIndex, aboveItemIndex;
        itemIndex = this.Options.SelectedIndex;
        aboveItemIndex = this.Options.SelectedIndex - 1;
        item = (string)this.Options.Items[itemIndex];
        aboveItem = (string)this.Options.Items[aboveItemIndex];

        this.Options.Items.RemoveAt(aboveItemIndex);
        this.Options.Items.Insert(itemIndex, aboveItem);
    }

Для кнопки вниз:

private void DownButton_Click(object sender, EventArgs e)
    {
        //this.Options is ListBox
        if (this.Options.SelectedIndex == -1 ||
                         this.Options.SelectedIndex >= this.Options.Items.Count)
            return;

        string item, belowItem;
        int itemIndex, belowItemIndex;
        itemIndex = this.Options.SelectedIndex;
        belowItemIndex = this.Options.SelectedIndex + 1;
        if (belowItemIndex >= this.Options.Items.Count)
            return;
        item = (string)this.Options.Items[itemIndex];
        belowItem = (string)this.Options.Items[belowItemIndex];

        this.Options.Items.RemoveAt(itemIndex);
        this.Options.Items.Insert(belowItemIndex, item);
        this.Options.SelectedIndex = belowItemIndex;
    }
0
Yasser-Taherkhani

Я написал эту функцию для перемещения выбранных элементов:

using System.Collections;
using System.Collections.Generic;

private void MoveListboxItems(int step, ListBox lb) {
    /* 'step' should be:
     *   -1 for moving selected items up
     *    1 for moving selected items down
     * 'lb' is your ListBox
     *   see examples how to call below this function
    */
    try {
        // do only something when really an item is selected
        if (lb.SelectedIndex > -1) {
            // get some needed values - they change while we manipulate the listbox
            // but we need them as they was original
            IList SelectedItems = lb.SelectedItems;
            IList SelectedIndices = lb.SelectedIndices;

            // set some default values
            int selIndex = -1;
            int newIndex = -1;
            int selCount = SelectedItems.Count;
            int lc = 0;
            int mc = 0;
            string moveOldValue = string.Empty;
            string selectedItemValue = string.Empty;

            if (step == 1) {
                mc = selCount - 1;
            } else {
                mc = lc;
            }
            // enter the loop through the selected items
            while (lc < selCount) {
                selectedItemValue = string.Empty;
                moveOldValue = string.Empty;

                try {
                    // get the item that should get moved
                    selectedItemValue = SelectedItems[mc].ToString();
                    selIndex = Convert.ToInt32(SelectedIndices[mc]);
                } catch {
                    selIndex = -1;
                }
                // gen index for new place
                newIndex = selIndex + step;
                try {
                    // get the old value from the place where the item get moved
                    moveOldValue = lb.Items[newIndex].ToString();
                } catch { /* do nothing */ }
                try {
                    if (!String.IsNullOrEmpty(selectedItemValue) && !String.IsNullOrEmpty(moveOldValue) && selIndex != -1 && newIndex != -1 && !lb.SelectedIndices.Contains(newIndex)) {
                        // move selected item
                        lb.Items.RemoveAt(newIndex);
                        lb.Items.Insert(newIndex, selectedItemValue);
                        // write old value back to the old place from selected item
                        lb.Items.RemoveAt(selIndex);
                        lb.Items.Insert(selIndex, moveOldValue);
                        // hold the moved item selected
                        lb.SetSelected(newIndex, true);
                    }
                } catch { /* do nothing */ }
                lc++;
                if (step == 1) {
                    mc -= step;
                } else {
                    mc = lc;
                }
            }
        }
    } catch { /* do nothing */ };
}

// examples how i call the function above
void BtnLbUp_Click(object sender, EventArgs e) {
    MoveListboxItems(-1, this.lbMyList);
}

void BtnLbDown_Click(object sender, EventArgs e) {
    MoveListboxItems(1, this.lbMyList);
}
0
anoCoder