将字典绑定到GridView

Question

参照此线程：Algorithm to count the time that occured on the same period，如何将字典绑定到GridView？请看看答案。

我尝试添加一个GridView，然后在后台代码：GV.DataSource = timeRangeCounts并将其绑定，但换来的：

The data source for GridView with id 'GV' did not have any properties or attributes from which to generate columns. Ensure that your data source has content.

我怎么能这样做？请看看下面的代码：

---

第一辅助类用来保持准确和子范围相匹配的计数：

Public Class TimeRangeCounter 
    Property ExactRangeMatch as Integer 
    Property SubRangeMatch as Integer 
End Class 

第二个辅助类是用来帮助词典知道如何（的TimeRange型）一个密钥不同于另一个：

Public Class TimeRangeEqualityComparer 
    Implements IEqualityComparer(Of TimeRange) 

    Public Overloads Function Equals(left As TimeRange, right As TimeRange) _ 
      As Boolean Implements IEqualityComparer(Of TimeRange).Equals   

     Return left.ToString = right.ToString 
    End Function 

    Public Overloads Function GetHashCode(range As TimeRange) _ 
      As Integer Implements IEqualityComparer(Of TimeRange).GetHashCode 

     return range.ToString().GetHashCode() 
    End Function 

End Class 

第三辅助类存储的范围的开始和结束时间：

Public Class TimeRange 
    Private readonly _start 
    Private readonly _end 

    Public Readonly Property Start 
     Get 
      return _start 
     End Get 
    End Property 

    Public Readonly Property [End] 
     Get 
      return _end 
     End Get 
    End Property 

    Public Sub New(start As String, [end] As string) 
     Me._start = start 
     Me._end = [end] 
    End Sub 

    Public Overrides Function ToString() as String 
     Return String.Format("{0}-{1}", Start, [End]) 
    End Function 

End Class 

因此，使用上面我们应该能够写这个算法：

Dim columnLength As Integer = 5 
Dim timeStart() As String = {"08.00", "08.00", "10.00", "08.00", "08.00"} 
Dim timeEnd() As String = {"08.50", "11.50", "11.00", "09.00", "08.50"} 
Dim comparer As New TimeRangeEqualityComparer() 
Dim timeRangeCounts As New Dictionary(Of TimeRange, TimeRangeCounter)(comparer) 

'Count exact range matches while building dictionary 
For i = 0 to columnLength - 1 
    Dim key As TimeRange = New TimeRange(timeStart(i), timeEnd(i)) 

    If timeRangeCounts.ContainsKey(key) 
     timeRangeCounts(key).ExactRangeMatch += 1 
    Else 
     Dim counter = New TimeRangeCounter() 
     counter.ExactRangeMatch = 1 
     timeRangeCounts(key) = counter 
    End If   

Next   

'Count sub ranges   
For Each kvp in timeRangeCounts 
    For Each key in timeRangeCounts.Keys 
     If kvp.key.Start >= key.Start AndAlso _ 
      kvp.Key.End <= key.End AndAlso _ 
      kvp.key.ToString <> key.ToString then   

      kvp.Value.SubRangeMatch += 1 
     End If 
    Next 
Next 

'Console.WriteLine(timeRangeCounts) 
    GV.DataSource = timeRangeCounts 
    GV.DataBind() 

GridView控件：

<asp:GridView ID="GV" runat="server"> 
    <Columns> 
     <asp:BoundField DataField="Key" HeaderText="Dictionary Key" /> 
     <asp:BoundField DataField="Value" HeaderText="Dictionary Value" /> 
    </Columns> 
</asp:GridView> 

然后我试图运行它，但结果是这样的：

Dictionary Key Dictionary Value 
08:00:00-08:50:00 TimeRangeCounter 
08:00:00-09:40:00 TimeRangeCounter 
10:00:00-11:40:00 TimeRangeCounter 
...    ... 

代码有什么问题？

Answer 1

这里是一个GridView

<asp:GridView ID="GV" runat="server" AutoGenerateColumns="false"> 
     <Columns> 
      <asp:BoundField DataField="Key" HeaderText="Dictionary Key" /> 
      <asp:BoundField DataField="Value" HeaderText="Dictionary Value" /> 
     </Columns> 
    </asp:GridView> 

这里是代码绑定字典到的GridView

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
    Dim D As New Dictionary(Of Integer, String) 
    D.Add(1, "One") 
    D.Add(2, "Two") 
    D.Add(3, "Three") 
    GV.DataSource = D 
    GV.DataBind() 
End Sub 

这里是输出

如果我的某些类型的“MyClass？”的值如何？

Gridview将根据“值”单元执行MyClass的ToString函数。

在你的榜样，重写ToString功能上该类

Public Class TimeRangeCounter 
    Property ExactRangeMatch as Integer 
    Property SubRangeMatch as Integer 
End Class 

这是必要的，因为你的“价值”是时间TimeRangeCounter

摘要

笔者的代码有两个问题。

• 问题1是产生实际误差，并通过下面的我的代码示例
• 问题2解决是缺乏用于在将GridView

“值”列中使用的自定义类一个ToString函数的