我使用 2 个下拉列表，每个都有一个 sqldatasource。我正在通过代码文件设置 sqldatasource 默认值，
我的代码是，
<tr>
<td>
Vehicle Type
</td>
<td>:</td>
<td>
<asp:Label ID="lblVehicle" runat="server" Text="" Visible="false"></asp:Label>
<asp:DropDownList ID="ddVehicleType" Visible="true" runat="server" CssClass="drop" AutoPostBack="True" AppendDataBoundItems="True"
DataSourceID="SqlDataSource2" DataTextField="VehicleName" DataValueField="VehicleTransId" OnSelectedIndexChanged="ddVehicleType_SelectedIndexChanged">
<asp:ListItem Value="0">-Select-</asp:ListItem>
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource2" runat="server" ConnectionString="<%$ ConnectionStrings:TAXIConnectionString %>"
SelectCommand="SELECT [VehicleName], [VehicleTransId] FROM [VehicleTransaction]">
</asp:SqlDataSource>
</tr>
<tr>
<td>
Vehicle Number
</td>
<td>:</td>
<td>
<asp:DropDownList ID="ddVehicleNumber" runat="server" CssClass="drop" AutoPostBack="false" AppendDataBoundItems="true" DataSourceID="SqlDataSource3" DataTextField="VehicleNumber" DataValueField="VehicleId">
<asp:ListItem Value="0">-Select-</asp:ListItem>
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource3" runat="server" ConnectionString="<%$ ConnectionStrings:TAXIConnectionString %>"
SelectCommand="SELECT [VehicleNumber], [VehicleId] FROM [VehicleMaster] as Master join VehicleTransaction as Trans
on Master.VehicleType=Trans.VehicleTransId
WHERE ( Trans.VehicleTransId = @Status and [Status] = @Status1) ">
<SelectParameters>
<asp:Parameter Name="Status" Type="String" />
<asp:Parameter DefaultValue="Available" Name="Status1" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
</td>
</tr>
.cs 文件是，
in page_load(){
if (!Page.IsPostBack)
{
SqlDataSource3.SelectParameters["Status"].DefaultValue = reader["VehicleId"].ToString();
}
protected void ddVehicleType_SelectedIndexChanged(object sender, EventArgs e)
{
string vehiclename = ddVehicleType.SelectedItem.Value;
SqlConnection con = new SqlConnection(System.Web.Configuration.WebConfigurationManager.ConnectionStrings["TAXIConnectionString"].ConnectionString);
con.Open();
string str = "select VehicleTransId from VehicleTransaction where VehicleTransId = '" + vehiclename + "'";
SqlCommand command = new SqlCommand(str, con);
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
SqlDataSource3.SelectParameters["Status"].DefaultValue = reader["VehicleTransId"].ToString();
//ddVehicleNumber.SelectedValue = reader["VehicleTransId"].ToString();
}
}
但下拉列表在调用“ddVehicleType_SelectedIndexChanged”函数后具有旧值...
帮我。