更改 DropDownList 并刷新 gridview

Question

我有一个下拉列表：

<asp:DropDownList class="form-control" runat="server" ID="ddlChangeStatus">
   <asp:ListItem Text="Under Review" value="1" />
   <asp:ListItem Text="Approved" value="2" /> 
   <asp:ListItem Text="Rejected" value="3" /> 
   <asp:ListItem Text="Logged" value="4" /> 
   <asp:ListItem Text="Completed" value="5" /> 
</asp:DropDownList>

当它改变时，我想用 DropDownList 的新值刷新 gridview。

protected void Page_Load(object sender, EventArgs e)
{
    using (dbPSREntities5 myEntities = new dbPSREntities5())
    {
        int theStatus = Convert.ToInt32(ddlChangeStatus.SelectedValue); <--- this is the value of the DropDownList

        var allDepartments = (from tbProject in myEntities.tbProjects
                              // inner join to department lookup table
                              from refDepartments in myEntities.refDepartments.Where(x => x.refDepartmentID == tbProject.refDepartmentID) // to do a left join instead of an inner, append .DefaultIfEmpty() after this where clause
                              from refBuildings in myEntities.refBuildings.Where(x => x.refBuildingID == tbProject.refBuildingID).DefaultIfEmpty()
                              //from tbBreadCrumb in myEntities.tbBreadCrumbs.Where(x => x.ProjectID == tbProject.ProjectID)
                              from tbBreadCrumb in myEntities.tbBreadCrumbs.Where(x => x.ProjectID == tbProject.ProjectID && x.BreadCrumbID == myEntities.tbBreadCrumbs.Where(y => y.ProjectID == tbProject.ProjectID).Max(y => y.BreadCrumbID) && x.StatusID == theStatus) <---- Here is where the DropDownList value alters the query
                              from refBreadCrumb in myEntities.refBreadCrumbs.Where(x => x.refBreadCrumbID == tbBreadCrumb.StatusID)
                              // select new anon type
                              select new
                              {
                                  ProjectID = tbProject.ProjectID,
                                  Status = refBreadCrumb.BreadCrumbValue,
                                  DateSubmitted = tbBreadCrumb.CreateDateTime,
                                  refDepartmentID = tbProject.refDepartmentID,
                                  refBuildingValue = refBuildings.refBuildingValue,
                                  ProjectContactFullName = tbProject.ProjectContactFirstName + " " + tbProject.ProjectContactLastName,
                                  ProjectWorkType = tbProject.ProjectWorkType,
                                  refDepartmentValue = refDepartments.refDepartmentValue,
                              }); // I chose to turn the result into a list to demonstrate something below, you can leave it as an enumerable.

        // bind to your listview, make sure control name is accurate and ItemTemplates are defined for each data column.
        projectsListView.DataSource = allDepartments;
        projectsListView.DataBind();
    }
}

不确定执行此操作的最佳方法。我尝试调用 Page_Load() 但这不起作用。基本上只是希望用户创建一个提交给页面加载的新选择，它运行刷新gridview的查询。提前致谢！

Answer 1

首先，在 DropDownList 控件中，需要添加 AutoPostBack="true"

其次，您可以在 DropDownList_SelectedIndexChanged 事件中的 Page_Load 事件中执行您正在执行的操作

我希望这会有所帮助。

Answer 2

下面的代码可以帮助你。

protected void Page_Load(object sender, EventArgs e)
    {

if(!IsPostback)
 // Bind the data to Gridview as ur business logic
}

protected void ddlChangeStatus_SelectedIndexChanged(object sender, EventArgs e)
    {
 // Bind the data to Gridview as ur business logic
}