如何在组合框中添加空白项目 [英] How to add blank item in combobox

问题描述

  public  void Bind（）
 {
 
 _initializing = true; 
 
 dataComboBox.DataBindings.Clear（）; 
 dataComboBox.SelectedIndex = -1; 
 dataComboBox。文本 =  ; 
 
 //我希望   insert 一个空项 in 数据源
 
 dataComboBox.DataSource = Model.ContAccesslist。插入（ 0 ，）; <   -   我需要插入的第二个参数是什么...  
 dataComboBox。 DisplayMember =   DataName; 
 dataComboBox.ValueMember =   id; 
 
} 
 
 
 BLL：
  public 列表< ContViewModel> ContAccesslist {get;  set ; } 
 
 DAL：
  public 类ContViewModel 
 {
  public   int  Id {get;  set ; } 
  public  string DataName {get;  set ; } 
  public  string DataType {get;  set ; } 
 
 
} 

提前致谢！ ！

解决方案

  var  items = Model.ContAccesslist; 
 items.Insert（ 0 ， new  ContViewModel（）{DataName =  ，DataType =  ，Id = -1}）; 
 dataComboBox.DataSource = items; 
 dataComboBox.DisplayMember =   DataName; 
 dataComboBox.ValueMember =   id; 

public void Bind()
        {

            _initializing = true;

            dataComboBox.DataBindings.Clear();
            dataComboBox.SelectedIndex = -1;
            dataComboBox.Text = "";

        // I want to insert an empty item in the datasource

            dataComboBox.DataSource = Model.ContAccesslist.Insert(0,); <-- What would be second parameter i need to insert...
            dataComboBox.DisplayMember = "DataName";
            dataComboBox.ValueMember = "id";
          
        }


BLL:
public List<ContViewModel> ContAccesslist { get; set; }

DAL:
public class ContViewModel
    {
        public int Id { get; set; }
        public string DataName { get; set; }
        public string DataType { get; set; }


    }

Thanks in advance!!!

解决方案

var items = Model.ContAccesslist;
items.Insert(0,new ContViewModel(){DataName ="", DataType="", Id =-1 } );
dataComboBox.DataSource = items;  
dataComboBox.DisplayMember = "DataName";
dataComboBox.ValueMember = "id";

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