DropDownList绑定及修改

一、DropDownList:
1、选项值保存到数据库：
   Hashtable ht=new Hashtable();//这里用Hashtable
   ht.Add("字段名"，DropDownListID.SelectedItem.Text.ToString());//保存选项Text
   ht.Add("字段名"，DropDownListID.SelectedItem.Value.ToString());//保存选项Value

2、选项值由数据库绑定到DropDownList：
   首先DropDownListID.ClearSelection();//清除选项
    DropDownListID.Items.FindByText(dr["字段名"].ToString()).Selected = true;//选项Text
    DropDownListID.Items.FindByValue(dr["字段名"].ToString()).Selected = true;//选项Value

二、RadioButtonList:
1、选项值保存到数据库(同DropDownList)：
   Hashtable ht=new Hashtable();//这里用Hashtable
   ht.Add("字段名"，RadioButtonListID.SelectedItem.Text.ToString());//保存选项Text
   ht.Add("字段名"，RadioButtonListID.SelectedItem.Value.ToString());//保存选项Value

2、选项值由数据库绑定到RadioButtonList
   string SelectItem = dr["字段名"].ToString();//将数据库中的选项值从DataRow中读出赋给变量SelectItem
   for (int i = 0; i < RadioButtonListID.Items.Count; i++)
   {//用for循环判断那项被选种
       if (RadioButtonListID.Items[i].Text == SelectItem)RadioButtonListID.Items[i].Selected = true;
   }

三、CheckBoxList:
1、选项值保存到数据库
   string SelectItem = "";//声明一个变量来接受选项
   for (int i = 0; i < CheckBoxListID.Items.Count; i++)
   {//用for循环将所有选项用","隔开连接起来
        if (CheckBoxListID.Items[i].Selected)
        {
            SelectItem = SelectItem + CheckBoxListID.Items[i].Value + ",";//选项后加","隔开
        }
   }
   ht.Add("字段名",SelectItem.ToString());

2、选项值由数据库绑定到CheckBoxList
   string SelectItem = dr["字段名"].ToString();
   string[] arrStr = SelectItem.Split(',');//字段是以","隔开
   foreach (string str in arrStr)
   {
       for (int i = 0; i <CheckBoxListID.Items.Count; i++)
       {
          if (this.CheckBoxListID.Items[i].Value == str)
          {
             this.CheckBoxListID.Items[i].Selected = true;
          }
       }
   }
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1.把数据绑定到CheckBoxList中

  protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                SqlConnection con = GetDBCon.GetCon();
                con.Open();
                SqlDataAdapter sda = new SqlDataAdapter("select * from admin", con);
                DataSet ds = new DataSet();
                sda.Fill(ds,"admin");
                this.CheckBoxList1.DataSource = ds.Tables[0];
                this.CheckBoxList1.DataTextField = "username";//绑定的字段名
                this.CheckBoxList1.DataValueField = "userid";//绑定的值
                this.CheckBoxList1.DataBind();
               
             
                
            }
        }

2.循环读取出来

 protected void CheckBoxList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.Lab2.Text = "";
            for (int i = 0; i < CheckBoxList1.Items.Count; i++)
            {
                if (this.CheckBoxList1.Items[i].Selected)
                {
                    this.Lab2.Text = this.Lab2.Text+CheckBoxList1.Items[i].Text+".";
                }
            }
        }