如何最好地在ASP.NET中填充HTML表?

时间:2020-03-05 18:47:36  来源:igfitidea点击:

这就是我所拥有的。有用。但是,有没有更简单或者更完善的方法呢?

ASPX页面

<asp:Repeater ID="RepeaterBooks" runat="server">
    <HeaderTemplate>
        <table class="report">
            <tr>
                <th>Published</th>
                <th>Title</th>
                <th>Author</th>
                <th>Price</th>
            </tr>
    </HeaderTemplate>
    <ItemTemplate>
            <tr>
                <td><asp:Literal ID="LiteralPublished" runat="server" /></td>
                <td><asp:Literal ID="LiteralTitle" runat="server" /></td>
                <td><asp:Literal ID="LiteralAuthor" runat="server" /></td>
                <td><asp:Literal ID="LiteralPrice" runat="server" /></td>
            </tr>
    </ItemTemplate>
    <FooterTemplate>
        </table>
    </FooterTemplate>
</asp:Repeater>

背后的ASPX.VB代码

Protected Sub Page_Load( ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    Dim db As New BookstoreDataContext
    RepeaterBooks.DataSource = From b In db.Books _
                               Order By b.Published _
                               Select b
    RepeaterBooks.DataBind()
End Sub

Sub RepeaterBooks_ItemDataBound( ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles RepeaterBooks.ItemDataBound
    If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem Then
        Dim b As Book = DirectCast(e.Item.DataItem, Book)
        DirectCast(e.Item.FindControl("LiteralPublished"), Literal).Text = "<nobr>" + b.Published.ToShortDateString + "</nobr>"
        DirectCast(e.Item.FindControl("LiteralTitle"), Literal).Text = "<nobr>" + TryNbsp(HttpContext.Current.Server.HtmlEncode(b.Title)) + "</nobr>"
        DirectCast(e.Item.FindControl("LiteralAuthor"), Literal).Text = "<nobr>" + TryNbsp(HttpContext.Current.Server.HtmlEncode(b.Author)) + "</nobr>"
        DirectCast(e.Item.FindControl("LiteralPrice"), Literal).Text = "<nobr>" + Format(b.Price, "c") + "</nobr>"
    End If
End Sub

Function TryNbsp(ByVal s As String) As String
    If s = "" Then
        Return " "
    Else
        Return s
    End If
End Function

解决方案

回答

在.Net 3.0+中,我们可以通过执行以下操作将ItemDataBound替换为asp:Literal:

<ItemTemplate>
            <tr>
                <td><%# Eval("published") %></td>
                ...

其中"已发布"是我们绑定到转发器的数据中的字段名称

编辑:
@Alassek:我认为反思的表现常常被过分强调。显然,我们需要对应用程序的性能进行基准测试,但是评估的命中率很可能以毫秒为单位。除非应用程序同时提供许多并发命中数据,否则这可能不是问题,并且使用Eval简化代码,并很好地分隔了演示文稿,因此是一个不错的解决方案。

回答

我同意Geoff的观点,唯一一次使用Literals的地方就是我们想对数据做一些不同的事情。例如,我们可能希望DueDate字段显示"今天"或者"昨天",而不是实际日期。

回答

@杰夫

这种Eval语句实际上是在2.0中添加的,但是如果性能很重要,则应避免使用Eval,因为它使用了Reflection。

中继器是一种很好的方法,尽管用代码生成表可能会更快:

ASPX页面:

<table class="report" id="bookTable" runat="server">
        <tr>
            <th>Published</th>
            <th>Title</th>
            <th>Author</th>
            <th>Price</th>
        </tr>
 </table>

背后的代码:

Protected Sub Page_Load( ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Not Page.IsPostback Then
        BuildTable()
    End If
End Sub

Private Sub BuildTable()
    Dim db As New BookstoreDataContext
    Dim bookCollection = from b in db.Books _
                         Order By b.Published _
                         Select b
    Dim row As HtmlTableRow
    Dim cell As HtmlTableCell

    For Each book As Books In bookCollection
        row = New HtmlTableRow()
        cell = New HtmlTableCell With { .InnerText = b.Published.ToShortDateString }
        row.Controls.Add(cell)
        cell = New HtmlTableCell With { .InnerText = TryNbsp(HttpContext.Current.Server.HtmlEncode(b.Title)) }
        row.Controls.Add(cell)
        cell = New HtmlTableCell With { .InnerText = TryNbsp(HttpContext.Current.Server.HtmlEncode(b.Author))
        row.Controls.Add(cell)
        cell = New HtmlTableCell With { .InnerText = Format(b.Price, "c") }
        row.Controls.Add(cell)
        bookTable.Controls.Add(row)
    Next

我想这取决于速度对我们有多重要。为了简单起见,我想我会选择Repeater。

回答

ALassek wrote:
  
  &hellip;generate the table in code&hellip;

我喜欢那种外观!由于拼写错误或者字段名称更改,似乎不太可能产生运行时异常。

回答

框架3.5引入的ListView控件可能是更好的解决方案。标记如下所示:

<asp:ListView runat="server" ID="ListView1" 
    DataSourceID="SqlDataSource1">
  <LayoutTemplate>
    <table runat="server" id="table1" runat="server" >
      <tr runat="server" id="itemPlaceholder" ></tr>
    </table>
  </LayoutTemplate>
  <ItemTemplate>
    <tr runat="server>
      <td runat="server">
        <asp:Label ID="NameLabel" runat="server" 
          Text='<%#Eval("Name") %>' />
      </td>
    </tr>
  </ItemTemplate>
</asp:ListView>

回答

这就是GridView的用途。

<asp:GridView runat="server" DataSourceID="SqlDataSource1">
   <Columns>
      <asp:BoundField HeaderText="Published" DataField="Published" />
      <asp:BoundField HeaderText="Author" DataField="Author" />
   </Columns>
</asp:GridView>

回答

我将使用GridView(或者DataGrid,如果我们使用的是ASP.NET的旧版本)。

<asp:GridView ID="gvBooks" runat="server" AutoGenerateColumns="False">
    <Columns>
        <asp:BoundField HeaderText="Published" DataField="Published" />
        <asp:BoundField HeaderText="Title" DataField="Title" />                     
        <asp:BoundField HeaderText="Author" DataField="Author" />
        <asp:BoundField HeaderText="Price" DataField="Price" />
    </Columns>
</asp:GridView>

有一些代码:

Private Sub gvBooksRowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvBooks.RowDataBound
     Select Case e.Row.RowType
        Case DataControlRowType.DataRow

            ''' Your code here '''

     End Select
End Sub

我们可以用类似的方式绑定它。我们需要RowDataBound事件。

回答

如果我们不需要ASP.NET处理的编辑功能,我将远离DataGrid和GridView ...它们提供了不必要的膨胀。