ViewModel
//属性定义
     Dictionary<int, string> _selGroupList;
        /// <summary>
        /// 分组下拉列表
        /// </summary>
        public Dictionary<int, string> selGroupList
        {
            get { return _selGroupList; }
            set
            {
                _selGroupList = value;
                NotifyOfPropertyChange("selGroupList");
            }
        }
        private int _Group;
        /// <summary>
        ///当前分组
        /// </summary>
        public int Group
        {
            get { return _Group; }
            set
            {
                _Group = value;
                NotifyOfPropertyChange(() => Group);
            }
        }

//初始化数据
 //界面数据
  public ModuleInfoViewModel(sys_Right_Module groupInfo, OperType type)
{
       GetGroupList();
       Group = groupInfo.GroupID;
}
 /// <summary> 
/// 初始化分组下拉数据
 /// </summary>
 public void GetGroupList()
 { 
Dictionary<int, string> dic = new Dictionary<int, string>();
 dic.Add(-1, "=请选择=");
 List<sys_Right_Group> groupList = DataBaseService.DataBaseServer<sys_Right_Group>.GetModelList(" IsActive=1 ");
 if (groupList != null)
 { 
  groupList.ForEach(x => 
  { 
    dic.Add(x.GroupID, x.GroupName); });
  } 
selGroupList = dic; 
Group = -1; //默认选中第一项 
}

View界面绑定：

ItemsSource数据源为字典数据

DisplayMemberPath="Value" 为显示字典数据的值

SelectedValuePath="Key"字典数据的键与 SelectedValue 类型对应

<ComboBox Grid.Row="8" Grid.Column="1" ItemsSource="{Binding selGroupList}" SelectedIndex="0"  SelectedValuePath="Key" 
    DisplayMemberPath="Value" SelectedValue="{Binding Group,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
    HorizontalAlignment="Left"  Width="252" Height="25"  IsEditable="True" Margin="5,3">
 </ComboBox>

 界面效果：

WPF的ComboBox数据绑定，使用Dictionary作为数据源