C#中的ComboBox控件

ComboBox简写为:cmb

主要属性:
DropDownStyle
如果想让用户只能点选,不能用键盘输入,则设为DropDownList

ComboBox.SelectionChangeCommitted 事件仅当用户更改组合框选择时(用鼠标点选)，才会引发 SelectionChangeCommitted。不要使用 SelectedIndexChanged 或 SelectedValueChanged 来捕获用户更改，因为以编程方式更改选择时，也会引发这些事件。

设置新的 ValueMember 属性会引发 ValueMemberChanged 和SelectedValueChanged 事件。

从数据库中取数据并添充到comboBox中(同时介绍ValueMember 属性),代码如下:
            cmbUser.DataSource = sqlDS.Tables[0];
            cmbUser.DisplayMember = "UserName"; //display context
            cmbUser.ValueMember = "UserId"; //real context

there is a table named user
UserId  UserName
001 tom
002 jack
003 marry
004 jack

when the programme is running,'tom','jack','marry','jack'will displayed in the comboBox,you clicked 'jack'(the first 'jack') the result is:
cmbUser.SelectedValue.ToString() = 002
cmbUser.Text = jack;

也可以将一个ArrayList绑定到comboBox代码如下:

可以把每行数据看成数据库中的一条记录,先自定义一个类保存每条记录:
public class UserIntType
        {
            private string _display;
            private string _val;

            public UserIntType(string display, string val)
            {
                this._display = display;
                this._val = val;
            }

            public string DisplayName
            {
                get { return this._display; }
            }

            public string ValueName
            {
                get { return this._val; }
            }
        }

        ///

        /// 初始化Cmb
        ///

        private void InitCmb()
        {
            ArrayList aryFld = new ArrayList();
            aryFld.Add(new UserIntType("已回报金额", "sumRM"));
            aryFld.Add(new UserIntType("应回报金额", "sumSR"));
            cmbFieldHb.DataSource = aryFld;
            cmbFieldHb.DisplayMember = "DisplayName";
            cmbFieldHb.ValueMember = "ValueName";
        }

 //引用
fld=cmbFieldHb.SelectedValue.ToString()

若DropDownStyle=DropDownList,则cmb.text初始为空,可以cmb.SelectedIndex = 0;来选择初始值.