转发器内下拉列表上的选定值

本文关键字：下拉列表 转发器 | 更新日期: 2023-09-27 17:56:54

我正在中继器中添加一个下拉列表。现在我需要为我的下拉列表设置一个选定的值。但我不是很成功。

private void PhysicianSource()
{
    DataSet ds = new DataSet();
    DataTable dt = ds.Tables.Add("Source");
    dt.Columns.Add("ID", Type.GetType("System.String"));
    dt.Columns.Add("Desc", Type.GetType("System.String"));
    Provider oProvider = new Provider();
    List<ProviderLabel> lstprovider = oProvider.RetrievePhysicianList();
    foreach (ProviderLabel item in lstprovider)
    {
        DataRow dr = dt.NewRow();
        dr[0] = item.ProviderCode.ID.ToString();
        dr[1] = item.Name.ToString();
        dt.Rows.Add(dr);
    }
    drpPhysicianCode.DataSource = ds;
    drpPhysicianCode.DataMember = "Source";
    drpPhysicianCode.DataTextField = "ID";
    drpPhysicianCode.DataValueField = "ID";
    drpPhysicianCode.DataBind();
}

asp.net

<asp:Repeater ID="rptrPatientList" runat="server" >
    <HeaderTemplate></HeaderTemplate>
    <ItemTemplate>
        <tr>
            <td class="style2">
            <asp:DropDownList  ID="DropDownList1"
                DataTextField="ID" runat="server"
                DataValueField="Desc"
                SelectedValue='<%# Eval("Code") %>'
                DataSource="ds">
            </asp:DropDownList>
            </td>
            </td>
        </tr>

我的代码上没有任何反应..帮助我伙计们，我只是一个初学者..非常感谢..

转发器内下拉列表上的选定值

嗨，伊恩·艾斯，最好稍微修改一下你的代码 

 <asp:Repeater ID="rptProductList" runat="server" OnItemDataBound="rptProductList_ItemDataBound">
 <ItemTemplate> 
<asp:DropDownList runat="server" ID="MyRepeater" AutoPostBack="true" OnSelectedIndexChanged="DropDownList_SelectedIndexChanged" >
</asp:DropDownList>
 </ItemTemplate>
 </asp:Repeater>

现在隐藏的代码应该是 

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

}
protected void rptProductList_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        DropDownList MyDropDown= (DropDownList)e.Item.FindControl("MyRepeater");
        if (MyDropDown!= null)
        {
           MyDropDown.DataSource =   fillDropDown(MyDropDown);
            MyDropDown.DataBind();
        }
    }
}


 private DataSet fillDropDown(DropDownList dropDown)
    {
     // get  your collection and return.
    }
protected void DropDownList_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList MyDropDown= (DropDownList)sender;
    string item = MyDropDown.SelectedValue;
}

希望上面的例子有帮助。

  1. 尝试在数据绑定后设置所选值
  2. 不要在每次回发时设置列表内容。检查 Page.IsPostBack（）。请注意，这仅在启用了视图状态时才有效。
//Declare Class Scoped DataSet and DataTable variables
DataSet ds;
DataTable dt;
//Bind repeater and DataSource method
private void PhysicianSource()
{
    ds = new DataSet();
    dt = ds.Tables.Add("Source");
    dt.Columns.Add("ID", Type.GetType("System.String"));
    dt.Columns.Add("Desc", Type.GetType("System.String"));
    Provider oProvider = new Provider();
    List<ProviderLabel> lstprovider = oProvider.RetrievePhysicianList();
    foreach (ProviderLabel item in lstprovider)
    {
        DataRow dr = dt.NewRow();
        dr[0] = item.ProviderCode.ID.ToString();
        dr[1] = item.Name.ToString();
        dt.Rows.Add(dr);
    }
    drpPhysicianCode.DataSource = ds;
    drpPhysicianCode.DataMember = "Source";
    drpPhysicianCode.DataTextField = "ID";
    drpPhysicianCode.DataValueField = "ID";
    drpPhysicianCode.DataBind();
}
//Repeater Item Data Bound event in which we would find Controls to be bound
//and set DataSource and SelectedValue
protected void rptrPatientList_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        DropDownList DropDownList1 = e.Item.FindControl("DropDownList1") as DropDownList;
        if (DropDownList1 != null)
        {
           DropDownList1.DataSource = dt;
           DropDownList1.DataBind();
           DropDownList1.SelectedValue = // DataBinder Eval 'Code' //;
        }
    }
}

<asp:Repeater ID="rptrPatientList" runat="server" OnItemDataBound="rptrPatientList_ItemDataBound">
    <HeaderTemplate></HeaderTemplate>
    <ItemTemplate>
        <tr>
            <td class="style2">
            <asp:DropDownList  ID="DropDownList1"
                DataTextField="ID" runat="server"
                DataValueField="Desc"
                SelectedValue='<%# Eval("Code") %>'
                DataSource="ds">
            </asp:DropDownList>
            </td>
            </td>
        </tr>

出现此问题的原因是下拉列表的绑定发生在转发器控件的绑定之后。您可以使用 HTML5 自定义属性将下拉值设置为自定义属性，然后在下拉列表数据绑定后将其设置为所选值。我已经使用 asp：ObjectDataSource 绑定了下拉列表

.ASPX 

<asp:Repeater ID="rptrPatientList" runat="server" >
    <HeaderTemplate></HeaderTemplate>
    <ItemTemplate>
        <tr>
            <td class="style2">
            <asp:DropDownList  ID="DropDownList1"
                DataTextField="ID" runat="server"
                DataValueField="Desc" 
SetValue='<%# Eval("Code") %>' datasourceid="dsCategory" 
datatextfield="ID" datavaluefield="desc" DataMember = "Source" onprerender="DropDownDataBinding">
            </asp:DropDownList>
<asp:ObjectDataSource ID="dsCategory" runat="server" SelectMethod="PhysicianSource" TypeName="WebApplication.WebForm1" />
            </td>
            </td>
        </tr>

代码隐藏

protected void DropDownDataBinding(object sender, EventArgs e) //Method to set the selected value on Category dropdown inside repeater
{
    DropDownList sel = (DropDownList)sender;
    sel.Value = sel.Attributes["SetValue"];
    ListItem li = new ListItem("<< Select >>", "");
    sel.Items.Insert(0,li);
}
protected DataSet PhysicianSource()
{
        DataSet ds = new DataSet();
DataTable dt = ds.Tables.Add("Source");
dt.Columns.Add("ID", Type.GetType("System.String"));
dt.Columns.Add("Desc", Type.GetType("System.String"));
Provider oProvider = new Provider();
List<ProviderLabel> lstprovider = oProvider.RetrievePhysicianList();
foreach (ProviderLabel item in lstprovider)
{
    DataRow dr = dt.NewRow();
    dr[0] = item.ProviderCode.ID.ToString();
    dr[1] = item.Name.ToString();
    dt.Rows.Add(dr);
}
return ds;
}
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