列表框刪除

Question

我有一個列表框，帶有2個按鈕，新建和刪除。新增項目到列表框中，刪除按鈕應該從列表框中刪除項目。列表框項目與從下面的文本框中存儲用戶輸入數據的類綁定。

private void AddListBox() 
    {   
     lstCondition.BeginUpdate(); 
     Condition cond = new Condition(""); 

     cond.Name = string.Format("Condition {0}", _selection.NetConditions.Count + 1); 
     _selection.NetConditions.Add(cond); 

     lstCondition.EndUpdate(); 

     lstCondition.SelectedItem = cond;      

     cboNetCondition.Properties.Items.Clear(); 
     cboNetCondition.Properties.Items.AddRange(NetCondition); 
     cboControlType.Properties.Items.Clear(); 
     cboControlType.Properties.Items.AddRange(ControlType); 
     cboFlowRate.Properties.Items.Clear(); 
     cboFlowRate.Properties.Items.AddRange(FlowRate); 
    } 

private void btnNew_Click(object sender, EventArgs e) 
     { 
      AddListBox(); 

     } 

cbo項目是組合框，其數據在條件類中綁定到列表框的每個實例。

public frmNetConditions(Condition condo, Selection selection) 
    { 
     InitializeComponent(); 
     _selection = selection; 
     lstCondition.DataSource = _selection.NetConditions; 
     condition = _selection.NetConditions.Count; 

    } 

private void btnDelete_Click(object sender, EventArgs e) 
    { 

     selectedCondition = (Condition)lstCondition.SelectedItem; 

     cboControlType.SelectedIndex = -1; 
     cboNetCondition.SelectedIndex = -1; 
     cboFlowRate.SelectedIndex = -1; 
     txtFlowRate.Text = string.Empty; 
     txtStatPressure.Text = string.Empty; 
     txtDampOpening.Text = string.Empty; 
     txtDensity.Text = string.Empty; 
     cboDensity.SelectedIndex = -1; 

     lstCondition.Items.Remove(lstCondition.SelectedItem); 
     lstCondition.Refresh(); 


    } 

按下這個刪除按鈕後，列表框仍然包含我想刪除的項目，我不確定這是爲什麼？

更新與數據源

public List<Condition> NetConditions { get { return _netconditions; } } 

Answer 1

正如已經建議，你應該綁定到一個BindingList<Condition>而不是List<Condition>。這使您可以更改數據源和控件（ListBox）以獲取更改通知。該代碼應該是這樣的：

lstCondition.ValueMember = "ConditionId"; 
lstCondition.DisplayMember = "Name"; 
lstCondition.DataSource = NetConditions; 

定義綁定後，在ListBox項目操作的正確方法是從datasource，而不是ListBox本身刪除：

// SelectedItem should be checked for null (no selection is an option) 
NetCondition.Remove((Condition)lstCondition.SelectedItem); 

但是，如果，你打算改變一個元素的屬性（所以，而不是列表本身），只有當你的元素（條件）實現了INotifyPropertyChanged接口時纔會通知控件。