ArgumentOutOfRangeException當添加第一項到綁定列表數據源

Question

我想使用BindingList作爲C＃中的數據源，但每當我嘗試將第一項添加到BindingList，我得到一個ArgumentOutOfRangeException拋出。 在我的項目中，我需要清除BindingList，並在將其設置爲DataSource後添加新​​項目。

BindingList<string> dataSource = new BindingList<string>(); 
myComboBox.DataSource = dataSource; 
dataSource.Add("something"); // Exception, here. 

我知道這個異常由.NET Framework處理，但我需要找到一種方法來避免它。

我也試過

List<DirectoryInfo> list = aList.ToList(); 
list.AddRange(bList); 

//set the index to -1 as suggested 
var index = myComboBox.SelectedIndex; 
myComboBox.SelectedIndex = -1; 

myComboBox.DataSource = null; 
bindingList.Clear(); 
bindingList.AddRange(list.Distinct()); 
if (bindingList.Count > 0) 
{ 
    //internal ArgumentOutOfRangeException here when binding 
    myComboBox.DataSource = bindingList; 
    myComboBox.SelectedIndex = index; 
} 
else 
    myComboBox.DataSource = null; 

謝謝你，這裏是調用堆棧

System.Windows.Forms.dll!System.Windows.Forms.ComboBox.SelectedIndex.set(int value) 
System.Windows.Forms.dll!System.Windows.Forms.ListControl.DataManager_PositionChanged(object sender, System.EventArgs e) 
System.Windows.Forms.dll!System.Windows.Forms.CurrencyManager.OnPositionChanged(System.EventArgs e) 
System.Windows.Forms.dll!System.Windows.Forms.CurrencyManager.ChangeRecordState(int newPosition, bool validating, bool endCurrentEdit, bool firePositionChange, bool pullData) 
System.Windows.Forms.dll!System.Windows.Forms.CurrencyManager.List_ListChanged(object sender, System.ComponentModel.ListChangedEventArgs e) 
System.dll!System.ComponentModel.BindingList<System.__Canon>.OnListChanged(System.ComponentModel.ListChangedEventArgs e) 
System.dll!System.ComponentModel.BindingList<System.__Canon>.FireListChanged(System.ComponentModel.ListChangedType type, int index) 
System.dll!System.ComponentModel.BindingList<System.__Canon>.InsertItem(int index, System.__Canon item) 
######.dll!System.Collections.ObjectModel.Collection<###########>.Add(######### item) 

Answer 1

Finaly，我擺脫我的問題！這是我找到的解決方案

首先，我將DataSource設置爲null，因爲當我啓動時BindingList總是空的。

comboBox1.DataSource = null; 

然後，當我需要更新的BindingList並添加一些項目我在這裏做這樣的事情

List<DirectoryInfo> list = aList.ToList(); 
list.AddRange(bList); 

BeginUpdate(); 
bindingList.Clear(); 
bindingList.AddRange(list.Distinct()); 
EndUpdate(); 

是的BeginUpdate和EndUpdate方法

private void BeginUpdate() 
{ 
    //if the DataSource is going to be empty, adding the first item will 
    //always trigger an ArgumentOutOfRangeException on the selected index. 
    //to avoid this, we must stop the binding during the modification of the list. 
    _Updating = true; 
    comboBox1.DataSource = null; 
} 

private void EndUpdate() 
{ 
    if (bindingList.Count > 0) 
    { 
     //the binding will set SelectedIndex to the old index when rebinding and it's possibily the wrong one. 
     //the good index is always 0 but we set the index to -1 before to be sure to be able to trigger the 
     //selectedIndex_changed method after _UpdatingRecentFolders is turn to false 
     comboBox1.DataSource = bindingList; 
     comboBox1.SelectedIndex = -1; 
     _Updating = false; 
     //I always want 0 but you can place the index you want 
     comboBox1.SelectedIndex = 0; 
    } 
    else 
    { 
     comboBox1.DataSource = null; 
     _Updating = false; 
     comboBox1.SelectedIndex = -1; 
    } 
} 

我也有selectedIndex_changed事件

private void comboBoxItem_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    if (!_Updating && comboBox1.SelectedIndex != -1) 
     aControl.SelectedItem = bindingList[comboBox1.SelectedIndex]; 
} 

我希望這會幫助別人！

Answer 2

嘗試這樣的事情在這裏被我只是測試在我的評論說一個例子

var blist = new BindingList<string>(); 
blist.Add("something"); 
blist.Add("something2"); 
comboBox1.DataSource = blist; 

如果您需要首先將其分配空白，請執行如下操作：

if(blist.Count > 0) 
{ 
    comboBox1.DataSource = null; 
    var blist = new BindingList<string>(); 
    blist.Add("something"); 
    blist.Add("something2"); 
    comboBox1.DataSource = blist; 
} 

做List<T>.Add方法或BindingList.Add方法 也看.Clear()方法和一些研究。 Count()方法

替代使用的BindingList會的BindingSource在這裏找到更多的閱讀關於這個主題MSDN BindingSource Class