数据库连接

 

SelectedItem(ListItem类。Text，value)
SelectedValue
SelectedIndex

Button
LinkButton
ImageButton

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选择类控件：
CheckBox复选框
允许用户选择true或者false状态，体现用户是否选择某个选项
 
CeckBoxList
RedioButton
RadioButtonList

图像控件：
Image
ImageMap

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数据库连接（从数据库调用）：
 if (!IsPostBack)
        {
            string strCnn = "data source=.;initial catalog=students;integrated security=true";
            SqlConnection sqlCnn = new SqlConnection(strCnn);
            SqlCommand sqlCmm = new SqlCommand();
            sqlCmm.Connection = sqlCnn;
            sqlCmm.CommandText = "SELECT * FROM PROVINCE";
            SqlDataReader reader = null;
            try
            {
                sqlCnn.Open();
                reader = sqlCmm.ExecuteReader();
                ListItem li;
                while (reader.Read())
                {
                    li = new ListItem(reader.GetString(1), reader.GetInt32(reader.GetOrdinal("id")).ToString());
                    this.DropDownList1.Items.Add(li);
                }
            }
            catch
            {
                //提示?
            }
            finally
            {
                reader.Close();
                sqlCnn.Close();
            }
        }

 

联动代码：
  string strCnn = "data source=.;initial catalog=students;integrated security=true";
        SqlConnection sqlCnn = new SqlConnection(strCnn);
        SqlCommand sqlCmm = new SqlCommand();
        sqlCmm.Connection = sqlCnn;
        sqlCmm.CommandText = "SELECT id,name FROM city WHERE provinceid=@pid";
        SqlParameter param = new SqlParameter("@pid", System.Data.SqlDbType.Int);
        param.Value = this.DropDownList1.SelectedValue;
        sqlCmm.Parameters.Add(param);
        SqlDataReader reader = null;
        try{
            sqlCnn.Open();
            reader = sqlCmm.ExecuteReader();
            this.DropDownList2.DataSource = reader;
            this.DropDownList2.DataTextField = "name";
            this.DropDownList2.DataValueField = "id";
            this.DropDownList2.DataBind();
        }
        catch{throw;}
        finally{
            reader.Close();
            sqlCnn.Close();
        }