modal 为空时的错误消息

Question

我的页面上有几个带有复选框的模式弹出窗口。复选框是可以添加到特定产品的不同项目。但是，有些产品分配了一种类型的项目。当模态框为空时，我需要一种在模态框中显示消息的方法。

我尝试在模式中使用“所有功能当前都与此产品相关联”的标签。但是当标签的可见性设置为隐藏时，标签会在模式中留下一个空间，这很烦人，所以我放弃了这个想法。

当模态框为空时显示隐藏消息的好方法是什么？

<asp:LinkButton ID="FeatureButton" runat="server">Feature</asp:LinkButton>
  <asp:Panel ID="FeaturePanel" runat="server" CssClass="modalPopup"
  Style="display:none">
     <div class="PopupHeader">Add a Feature</div>
       <asp:CheckBoxList ID="cbxAddFeature" runat="server" 
       DataSourceID="dsNewFeatures" DataTextField="FeatureTitle"
       DataValueField="FeatureID"></asp:CheckBoxList>
       **<asp:Label ID="FeatureError" runat="server" 
       Text="All features are currently associated to this product." 
       Display="none"></asp:Label>**
         <asp:Button ID="SubmitFeatures" runat="server" Text="Submit" />
         <asp:Button ID="CancelSubmitFeatures" runat="server" Text="Cancel" />
   </asp:Panel>
<asp:ModalPopupExtender ID="FeatureModal" runat="server" 
BackgroundCssClass="modalBackground" CancelControlID="CancelSubmitFeatures"
DropShadow="True" DynamicServicePath="" Enabled="True" 
PopupControlID="FeaturePanel" TargetControlID="FeatureButton">
</asp:ModalPopupExtender>   


Protected Sub SubmitFeatures_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Handles SubmitFeatures.Click
FeatureModal.Hide()
For Each feature As ListItem In cbxAddFeature.Items
**FeatureError.Visible = False**
If feature.Selected Then
'SQL INSERT: Marketing Table
Dim strSQL As String = "INSERT INTO Marketing (ProductID, MarketingTypeID, MarketingTitle, MarketingData) VALUES (@ProductID, 3, 'Feature', @MarketingData)"

Using cn As New   SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings("LocalSqlServer").ConnectionString)

Using cmd As New SqlCommand(strSQL, cn)

cmd.Parameters.Add(New SqlParameter("@ProductID", ProductID.Value))
cmd.Parameters.Add(New SqlParameter("@MarketingData", feature.Value))

cn.Open()

cmd.ExecuteNonQuery()
End Using
End Using
End If
**If (dsNewFeatures) == DBNull.Value Then
  FeatureError.Visible = True
End If**
 Next
 Response.Redirect(Request.RawUrl)
End Sub

<asp:SqlDataSource ID="dsNewFeatures" runat="server" 
    ConnectionString="<%$ ConnectionStrings:ProductsConnectionString %>" 
    ProviderName="<%$ ConnectionStrings:ProductsConnectionString.ProviderName %>" 
    SelectCommand="SELECT DISTINCT f.FeatureID, f.FeatureTitle 
    FROM Feature f LEFT JOIN Category c ON c.CategoryID = f.CategoryID 
    WHERE f.CategoryID IN 
    (SELECT CategoryID FROM CategoryLink 
    WHERE ProductID = @ProductID) AND f.FeatureID NOT IN 
    (SELECT m.MarketingData FROM Marketing m 
    WHERE m.MarketingTypeID = 3 AND m.ProductID = @ProductID) 
    ORDER BY f.FeatureTitle">
    <SelectParameters>
        <asp:QueryStringParameter Name="ProductID" QueryStringField="id" />
    </SelectParameters>
    <SelectParameters>
        <asp:QueryStringParameter Name="CategoryID" QueryStringField="id" />
    </SelectParameters>
</asp:SqlDataSource>

所有 **** 项都是标签的一部分，If, End If 语句不起作用，有谁知道我可以如何更改它以找到错误消息的空模式？

这就是现在的样子，注意显示的标签。我不知道为什么它不会消失！

编辑 9/29/11

Protected Sub dsNewFeatures_Selected(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.SqlDataSourceStatusEventArgs) Handles dsNewFeatures.Selected
    If FeatureError.Text = String.Format("rows count: {0}", e.AffectedRows) Then
        FeatureError.Visible = True
    Else
        FeatureError.Visible = False
    End If
End Sub

它几乎可以工作！仅根据此代码，标签不可见，但是当我清空模式时无法取消隐藏

Answer 1

当您说it's visibility is set to hidden 时，您指的是 CSS 可见性属性？如果是这样，请尝试改用display:none，这应该可以解决您不喜欢的间距问题。

如果那不这样做（我认为它会），只需在触发弹出对话框的事件时在后面的代码中将标签的 Visible 属性设置为 false。我相信当 Visible 属性为 false 时 ASP.NET 不会呈现元素，所以这肯定可以工作。

我的意思是：

annoyingLabel.Visisble=False

您可以根据是否需要显示消息相应地切换 Visible 属性。

希望这会有所帮助。

更新：

How about this?

Dim showNextTime As Boolean = False
If feature.Selected Then
  '' your code here
Else 
   showNextTime =True 
End If

FeatureError.Visible = showNextTime

由于您正在遍历所有项目并检查它们是否被选中，所以您需要做的就是设置一个标志，当其中一个项目未被选中时该标志将变为真（意思是，至少会有一个项目待补充）。

如果没有要通过的项目，则默认情况下 FeatureError.Visible 应该为 false。

这对你有用吗？

更新 2

Dim showNextTime As Boolean = False
If feature.Selected Then
  '' your code here
Else 
   showNextTime =True 
End If
' Add this condition to make it visible if Items.Count==0 
FeatureError.Visible = (showNextTime Or cbxAddFeature.Items.Count==0)

更新 3 现在试试这个：

向您的 FeatureButton 添加一个 OnCLick 事件，如下所示：

<asp:LinkButton OnClick="FeatureButton_Click" ID="FeatureButton" runat="server">Feature</asp:LinkButton>

在你的代码后面：

  Sub FeatureButton_Click(sender As Object, e As EventArgs) 
     FeatureError.Visible = (cbxAddFeature.Items.Count=0)
  End Sub

我们将完成这项工作。

更新 4： 将您的 OnSelected 代码更改为此（我不知道您为什么要比较文本）：

Protected Sub dsNewFeatures_Selected(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.SqlDataSourceStatusEventArgs) Handles dsNewFeatures.Selected
    If  e.AffectedRows=0 Then
        FeatureError.Visible = True
        FeatureError.Text= "All features are currently associated to this product." 
    Else
        FeatureError.Text= "" 
        FeatureError.Visible = False
    End If
End Sub

Answer 2

由于 asp.net 控制幕后可见性的方式，您得到了空白。当控件呈现给浏览器时，它的 css 样式设置为visibility: hidden，这将在文档中元素应该存在的位置留下空白。如果要删除空白，则必须使用 css 样式display: none。

因此，在您的代码中： 改变

<asp:Label ID="FeatureError" runat="server" 
       Text="All features are currently associated to this product." 
       Display="none"></asp:Label>

到

<asp:Label ID="FeatureError" runat="server" 
       Text="All features are currently associated to this product."></asp:Label>

改变

For Each feature As ListItem In cbxAddFeature.Items
**FeatureError.Visible = False**
....

到

 For Each feature As ListItem In cbxAddFeature.Items
    FeatureError.Attributes.Add("Style", "Display: None;")
...

改变

**If (dsNewFeatures) == DBNull.Value Then
  FeatureError.Visible = True
End If**

到

Dim dv as DataView
dv = CType(dsNewFeatures.Select(DataSourceSelectArguments.Empty), DataView)
If(dv.Count == 0)
  FeatureError.Attributes("Style") = "Display: Inline;"
End If

如果需要，您还可以将样式重构为样式表中。

参考： Visibility vs Display in CSS