在页面之间导航时如何使 DropDownList 保留选定的值
How can I make DropDownList retain selected value when navigating between pages
如能提供以下任何帮助，我们将不胜感激...
我的页面上有三个 DropDownList，我在 Page_Load 事件中绑定数据（不是 Page.IsPostBack）。
用户将从 DropDownLists select 值导航到不同的页面。如果他们然后 select 到 'Go Back' 到初始页面，DropDownLists 总是重置到他们的字母列表的顶部。
有什么方法可以修改它以记住用户最后输入的值吗？
我希望这些信息足够了。
提前致谢。
.aspx
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<h2>
Amend Checklist</h2>
<br /><br />
<table>
<tr>
<td>
Team
</td>
<td>
<asp:DropDownList ID="drpTeam" runat="server" AutoPostBack="true">
</asp:DropDownList>
</td>
<td>
Category
</td>
<td>
<asp:DropDownList ID="drpCategory" runat="server" AutoPostBack="true">
</asp:DropDownList>
</td>
<td>
Management Company
</td>
<td>
<asp:DropDownList ID="drpManCo" runat="server">
</asp:DropDownList>
</td>
</tr>
</table>
.aspx.vb
Protected Overloads Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Try
Me.Header.Title = "OCP - Checklist Admin"
'security
If Not (secHelper.HasRole(SecurityMatchOption.AtLeast, SecurityRole.Manager)) Then
Server.Transfer("~/dialogs/accessdenied.aspx")
End If
' querystring passed through from the btnAdd_Click Response.Redirect to display success message - WT214900 - 16.01.15 - GJust
If Request.QueryString("alert") = "Checklistadded" Then
lblSuccess.Text = "Checklist Created Successfully"
End If
If (Not Page.IsPostBack) Then
secHelper.BindTeamDropDown(drpTeam, SecurityMatchOption.AtLeast, SecurityRole.Manager)
GetAllCategoriesForAllTeams()
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer))
PopulateManCoDropdown(drpManCo)
BindChecklistRepeater()
' set up any default button handlers
btnBack.PostBackUrl = "~/Default.aspx"
End If
'BindChecklistRepeater()
Catch ex As Exception
ExceptionHelper.HandleException(ex)
End Try
End Sub
Private Sub GetAllCategoriesForAllTeams()
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
For Each team In secHelper.GetTeamsForUser()
Dim currentTeam As Team = team
Dim category As List(Of Category) = db.Categories.Where(CType(Function(x) CType(x.team_id = currentTeam.id, Boolean), Func(Of Category, Boolean))).ToList()
_allCategories.AddRange(category)
Session(Constants.SESSION_ALLCATEGORIES) = _allCategories
Next
End Using
End Sub
Private Sub PopulateCategoryDropDown(ByRef drp As System.Web.UI.WebControls.DropDownList, Optional ByVal teamId As Integer? = Nothing)
If teamId Is Nothing Then
drp.DataSource = CType(Session(Constants.SESSION_ALLCATEGORIES), List(Of Category)).Distinct().OrderBy(Function(c) c.name).ToList()
Else
drp.DataSource = CType(Session(Constants.SESSION_ALLCATEGORIES), List(Of Category)).Distinct().Where(Function(c) CType(c.team_id = teamId, Boolean)).OrderBy(Function(c) c.name).ToList()
End If
drp.DataTextField = "name"
drp.DataValueField = "id"
drp.DataBind()
End Sub
Private Sub PopulateManCoDropdown(ByRef drp As DropDownList)
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
drp.DataSource = db.ManCos().OrderBy(Function(mc) mc.name).ToList()
drp.DataTextField = "name"
drp.DataValueField = "id"
drp.DataBind()
drp.Items.Insert(0, New ListItem("<No Management Company>", String.Empty))
End Using
End Sub
Private Sub drpTeam_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles drpTeam.SelectedIndexChanged
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer?))
BindChecklistRepeater()
GetAllCategoriesForAllTeams()
End Sub
Private Sub drpCategory_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles drpCategory.SelectedIndexChanged
BindChecklistRepeater()
End Sub
Protected Sub drpTeamRepeater_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim drpTm As DropDownList = CType(sender, DropDownList)
PopulateCategoryDropDown(CType(drpTm.NamingContainer.FindControl("drpCategory"), DropDownList), CType(drpTm.SelectedValue, Integer?))
End Sub
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAdd.Click
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
Dim newCheckList As New Model.Checklist
newCheckList.name = txtChecklist.Text
newCheckList.team_id = CInt(drpTeam.SelectedItem.Value)
newCheckList.category_id = CInt(drpCategory.SelectedItem.Value)
newCheckList.status = Constants.CHECKLIST_STATUS_CREATED
If (drpManCo.SelectedItem.Value = String.Empty) Then
newCheckList.manco_id = Nothing
Else
newCheckList.manco_id = CInt(drpManCo.SelectedItem.Value)
End If
db.Checklists.InsertOnSubmit(newCheckList)
db.SubmitChanges()
BindChecklistRepeater()
'Response.Redirect("~/admin/Tasks.aspx?chkid=" + newCheckList.id.ToString())
' Redirect user to the same page with query string. This prevents form resubmission if/when the user refreshes browser [F5] - WT214889 - 14.01.15 - GJust
Response.Redirect("~/admin/ChecklistAdmin.aspx?alert=Checklistadded")
End Using
End Sub
Private Sub BindChecklistRepeater()
If (Not drpTeam.SelectedItem Is Nothing AndAlso Not drpCategory.SelectedItem Is Nothing) Then
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
Dim checklists As List(Of Model.Checklist) = _
db.Checklists.Where(Function(x) x.team_id = CInt(drpTeam.SelectedItem.Value) AndAlso x.category_id = CInt(drpCategory.SelectedItem.Value)). _
OrderBy(Function(c) c.name).ToList() ' Fix issue 69 - added OrderBy
Dim teamId = CType(drpTeam.SelectedValue, Integer)
' Released Checklists
ChecklistAdminRepeaterReleased.Bind(teamId, Constants.ChecklistStatus.RELEASED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_RELEASED).ToList())
' Created Checklists
ChecklistAdminRepeaterCreated.Bind(teamId, Constants.ChecklistStatus.CREATED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_CREATED).ToList())
' Archived Checklists
ChecklistAdminRepeaterArchived.Bind(teamId, Constants.ChecklistStatus.ARCHIVED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_ARCHIVED).ToList())
lblMessage.Text = String.Empty
pnlEdit.Visible = True
If (checklists.Count <= 0) Then
lblMessage.Text = "No checklist found"
pnlEdit.Visible = False
End If
End Using
End If
End Sub
在单个会话对象中维护所有三个值，这些值由一些字符分隔，例如会话['ddlvalues']="ddlval1#ddlval2#ddlval3"
当您返回初始页面时，检查会话 ["ddlvalues"] 使用您使用的特殊字符和 select 下拉列表中的值拆分字符串
我通过使用 Session 存储我的选择解决了这个问题，并在页面加载时重新评估。
Session("Team") = drpTeam.SelectedValue
Session("Category") = drpCategory.SelectedValue
页面加载
If (Not Page.IsPostBack) And Session("Team") IsNot Nothing Then
drpTeam.SelectedValue = Session("Team").ToString()
drpCategory.SelectedValue = Session("Category").ToString()
secHelper.BindTeamDropDown(drpTeam, SecurityMatchOption.AtLeast, SecurityRole.Manager)
GetAllCategoriesForAllTeams()
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer))
PopulateManCoDropdown(drpManCo)
BindChecklistRepeater()
End If
如能提供以下任何帮助，我们将不胜感激...
我的页面上有三个 DropDownList，我在 Page_Load 事件中绑定数据（不是 Page.IsPostBack）。
用户将从 DropDownLists select 值导航到不同的页面。如果他们然后 select 到 'Go Back' 到初始页面，DropDownLists 总是重置到他们的字母列表的顶部。
有什么方法可以修改它以记住用户最后输入的值吗？
我希望这些信息足够了。
提前致谢。
.aspx
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<h2>
Amend Checklist</h2>
<br /><br />
<table>
<tr>
<td>
Team
</td>
<td>
<asp:DropDownList ID="drpTeam" runat="server" AutoPostBack="true">
</asp:DropDownList>
</td>
<td>
Category
</td>
<td>
<asp:DropDownList ID="drpCategory" runat="server" AutoPostBack="true">
</asp:DropDownList>
</td>
<td>
Management Company
</td>
<td>
<asp:DropDownList ID="drpManCo" runat="server">
</asp:DropDownList>
</td>
</tr>
</table>
.aspx.vb
Protected Overloads Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Try
Me.Header.Title = "OCP - Checklist Admin"
'security
If Not (secHelper.HasRole(SecurityMatchOption.AtLeast, SecurityRole.Manager)) Then
Server.Transfer("~/dialogs/accessdenied.aspx")
End If
' querystring passed through from the btnAdd_Click Response.Redirect to display success message - WT214900 - 16.01.15 - GJust
If Request.QueryString("alert") = "Checklistadded" Then
lblSuccess.Text = "Checklist Created Successfully"
End If
If (Not Page.IsPostBack) Then
secHelper.BindTeamDropDown(drpTeam, SecurityMatchOption.AtLeast, SecurityRole.Manager)
GetAllCategoriesForAllTeams()
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer))
PopulateManCoDropdown(drpManCo)
BindChecklistRepeater()
' set up any default button handlers
btnBack.PostBackUrl = "~/Default.aspx"
End If
'BindChecklistRepeater()
Catch ex As Exception
ExceptionHelper.HandleException(ex)
End Try
End Sub
Private Sub GetAllCategoriesForAllTeams()
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
For Each team In secHelper.GetTeamsForUser()
Dim currentTeam As Team = team
Dim category As List(Of Category) = db.Categories.Where(CType(Function(x) CType(x.team_id = currentTeam.id, Boolean), Func(Of Category, Boolean))).ToList()
_allCategories.AddRange(category)
Session(Constants.SESSION_ALLCATEGORIES) = _allCategories
Next
End Using
End Sub
Private Sub PopulateCategoryDropDown(ByRef drp As System.Web.UI.WebControls.DropDownList, Optional ByVal teamId As Integer? = Nothing)
If teamId Is Nothing Then
drp.DataSource = CType(Session(Constants.SESSION_ALLCATEGORIES), List(Of Category)).Distinct().OrderBy(Function(c) c.name).ToList()
Else
drp.DataSource = CType(Session(Constants.SESSION_ALLCATEGORIES), List(Of Category)).Distinct().Where(Function(c) CType(c.team_id = teamId, Boolean)).OrderBy(Function(c) c.name).ToList()
End If
drp.DataTextField = "name"
drp.DataValueField = "id"
drp.DataBind()
End Sub
Private Sub PopulateManCoDropdown(ByRef drp As DropDownList)
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
drp.DataSource = db.ManCos().OrderBy(Function(mc) mc.name).ToList()
drp.DataTextField = "name"
drp.DataValueField = "id"
drp.DataBind()
drp.Items.Insert(0, New ListItem("<No Management Company>", String.Empty))
End Using
End Sub
Private Sub drpTeam_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles drpTeam.SelectedIndexChanged
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer?))
BindChecklistRepeater()
GetAllCategoriesForAllTeams()
End Sub
Private Sub drpCategory_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles drpCategory.SelectedIndexChanged
BindChecklistRepeater()
End Sub
Protected Sub drpTeamRepeater_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim drpTm As DropDownList = CType(sender, DropDownList)
PopulateCategoryDropDown(CType(drpTm.NamingContainer.FindControl("drpCategory"), DropDownList), CType(drpTm.SelectedValue, Integer?))
End Sub
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAdd.Click
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
Dim newCheckList As New Model.Checklist
newCheckList.name = txtChecklist.Text
newCheckList.team_id = CInt(drpTeam.SelectedItem.Value)
newCheckList.category_id = CInt(drpCategory.SelectedItem.Value)
newCheckList.status = Constants.CHECKLIST_STATUS_CREATED
If (drpManCo.SelectedItem.Value = String.Empty) Then
newCheckList.manco_id = Nothing
Else
newCheckList.manco_id = CInt(drpManCo.SelectedItem.Value)
End If
db.Checklists.InsertOnSubmit(newCheckList)
db.SubmitChanges()
BindChecklistRepeater()
'Response.Redirect("~/admin/Tasks.aspx?chkid=" + newCheckList.id.ToString())
' Redirect user to the same page with query string. This prevents form resubmission if/when the user refreshes browser [F5] - WT214889 - 14.01.15 - GJust
Response.Redirect("~/admin/ChecklistAdmin.aspx?alert=Checklistadded")
End Using
End Sub
Private Sub BindChecklistRepeater()
If (Not drpTeam.SelectedItem Is Nothing AndAlso Not drpCategory.SelectedItem Is Nothing) Then
Using db As New LINQDataContext(Model.helpers.ConnectionHelper.ConnectionString())
Dim checklists As List(Of Model.Checklist) = _
db.Checklists.Where(Function(x) x.team_id = CInt(drpTeam.SelectedItem.Value) AndAlso x.category_id = CInt(drpCategory.SelectedItem.Value)). _
OrderBy(Function(c) c.name).ToList() ' Fix issue 69 - added OrderBy
Dim teamId = CType(drpTeam.SelectedValue, Integer)
' Released Checklists
ChecklistAdminRepeaterReleased.Bind(teamId, Constants.ChecklistStatus.RELEASED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_RELEASED).ToList())
' Created Checklists
ChecklistAdminRepeaterCreated.Bind(teamId, Constants.ChecklistStatus.CREATED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_CREATED).ToList())
' Archived Checklists
ChecklistAdminRepeaterArchived.Bind(teamId, Constants.ChecklistStatus.ARCHIVED, checklists.Where(Function(c) c.status = Constants.CHECKLIST_STATUS_ARCHIVED).ToList())
lblMessage.Text = String.Empty
pnlEdit.Visible = True
If (checklists.Count <= 0) Then
lblMessage.Text = "No checklist found"
pnlEdit.Visible = False
End If
End Using
End If
End Sub
在单个会话对象中维护所有三个值，这些值由一些字符分隔，例如会话['ddlvalues']="ddlval1#ddlval2#ddlval3" 当您返回初始页面时，检查会话 ["ddlvalues"] 使用您使用的特殊字符和 select 下拉列表中的值拆分字符串
我通过使用 Session 存储我的选择解决了这个问题，并在页面加载时重新评估。
Session("Team") = drpTeam.SelectedValue
Session("Category") = drpCategory.SelectedValue
页面加载
If (Not Page.IsPostBack) And Session("Team") IsNot Nothing Then
drpTeam.SelectedValue = Session("Team").ToString()
drpCategory.SelectedValue = Session("Category").ToString()
secHelper.BindTeamDropDown(drpTeam, SecurityMatchOption.AtLeast, SecurityRole.Manager)
GetAllCategoriesForAllTeams()
PopulateCategoryDropDown(drpCategory, CType(drpTeam.SelectedValue, Integer))
PopulateManCoDropdown(drpManCo)
BindChecklistRepeater()
End If