c#(winform)中自定义ListItem类方便ComboBox添加Item项
一，定义ListItem类

 public class ListItem
    {
        private string _key = string.Empty;
        private string _value = string.Empty;
        public ListItem(string pKey, string pValue)
        {
            _key = pKey;
            _value = pValue;
        }
        public override string ToString()
        {
            return this._value;
        }
        public string Key
        {
            get
            {
                return this._key;
            }
            set
            {
                this._key = value;
            }
        }
        public string Value
        {
            get
            {
                return this._value;
            }
            set
            {
                this._value = value;
            }
        }
    }

二，使用

ListItem listItem1 = new ListItem("1","中国");
ListItem listItem2 = new ListItem("1","美国");
ListItem listItem3 = new ListItem("1","英国");

comboBox1.Items.Add(listItem1);
comboBox1.Items.Add(listItem2);
comboBox1.Items.Add(listItem3);

三，取值

string id = ((ListItem)comboBox1.SelectedItem).Key;
string value = ((ListItem)comboBox1.SelectedItem).Value;

四、默认选中项
comboBox1.SelectedIndex = 0;//设置第一项为默认选择项
comboBox1.SelectedItem = listItem1//设置指定的项为默认选择项