DropDownList的反复数据值字段OnSelected感到困惑，并选择第一个，为什么？ [英] DropDownList with repeated data value fields OnSelected get confused and chooses the first one why?

问题描述

当前问题：我的DropDownList设有DataTextField =COLUMNS_NAMEDataValueField =DATA_TYPE属性时，DropDownList_SelectedIndexChanged（）不保留的基础上选定的输入文本。但它保留从项目的列表

的第一个值

解决方案所需的：如何留住基础上，DATA_TYPE属性选择输入的文本？ 我试图存储会话[DDLValue] = DropDownList.SelectedItem.Text ，但它始终保留了满足索引中的各自的DATA_TYPE present项目列表中的第一个值。

即。如果让我选择的E从以下DropDownList中输入保留在DropDownList中值为D

如何留住E

  COLUMN_NAME DATA_TYPE
十进制
b十进制
ç小数
ðINT
ËINT
˚FVARCHAR
摹VARCHAR
^ h VARCHAR
我为varchar
ĴVARCHAR
 

.aspx的code：

 ＆LT; ASP：DropDownList的ID =DropDownList5=服务器的AutoPostBack =真OnSelectedIndexChanged =DropDownList5_SelectedIndexChanged的DataSourceID =MySqlDataSource＆GT;
＆LT; / ASP：DropDownList的＆GT;
＆LT; ASP：SqlDataSource的ID =MySqlDataSource=服务器＆GT;
＆LT; / ASP：SqlDataSource的＆GT;
 

C＃code：

 保护无效的Page_Load（对象发件人，EventArgs的发送）
{
    如果（！的IsPostBack）
    {
        BindDropDownLists（）;
    }
}私人无效BindDropDownLists（）
{
    MySqlDataSource.ConnectionString =连接;
    MySqlDataSource.SelectCommand =SELECT DATA_TYPE +'_'+转换（VARCHAR（10），ROW_NUMBER（）OVER（ORDER BY DATA_TYPE））作为DATA_TYPE，COLUMN_NAME information_schema.columns在（TABLE_NAME ='结果'AND COLUMN_NAME IN（'列1 '，'列2'，'栏3'））;    DropDownList5.DataTextField =COLUMN_NAME;
    DropDownList5.DataValueField =DATA_TYPE;
    DropDownList5.DataBind（）;}
 

解决方案

渲染后，您的下拉列表看起来像下面的需要使用独特的价值领域的正确选择

Current Issue: My DropDownList is provided with DataTextField="COLUMNS_NAME" DataValueField="DATA_TYPE" properties, the DropDownList_SelectedIndexChanged() does not retain the text based on the selected input. But it retains the first value from the list of items

Solution Required: How to Retain the selected input text based on the DATA_TYPE property ? I tried storing the Session["DDLValue"] = DropDownList.SelectedItem.Text but it always retains the first value from the list of items which satisfies the respective DATA_TYPE present in an Index.

i.e. if i choose "e" from The following DropDownList inputs the value retained in DropDownList is "d"

How to retain "e"

COLUMN_NAME  DATA_TYPE  
a            decimal
b            decimal
c            decimal
d            int
e            int
f            varchar
g            varchar  
h            varchar
i            varchar
j            varchar

Aspx Code:

<asp:DropDownList ID="DropDownList5" runat="server"  AutoPostBack="true" OnSelectedIndexChanged ="DropDownList5_SelectedIndexChanged" DataSourceID="MySqlDataSource">
</asp:DropDownList>
<asp:SqlDataSource ID="MySqlDataSource" runat="server">
</asp:SqlDataSource>

C# code:

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        BindDropDownLists();
    }
}

private void BindDropDownLists()
{
    MySqlDataSource.ConnectionString = connection;
    MySqlDataSource.SelectCommand =  "SELECT DATA_TYPE + '_' + convert(varchar(10), ROW_NUMBER() OVER(ORDER BY DATA_TYPE ))as DATA_TYPE, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE (TABLE_NAME = 'RESULT' AND COLUMN_NAME IN ('Column1','column2','Column3'))";

    DropDownList5.DataTextField = "COLUMN_NAME";
    DropDownList5.DataValueField = "DATA_TYPE";
    DropDownList5.DataBind();

}

解决方案

After render , your drop down list is look like below , need to use unique value field for proper selection

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