在后面的代码中找不到动态创建的TD

Question

我在代码中创建了一个动态表，在后面加载页面。我已经创建了一个按钮，当单击该按钮时，我需要在表中的特定<td>中添加一个<td>。但是，它没有使用id找到我的<td>元素。我做错了什么？

Function CalendarRefresh(Day As Integer, MonthDays As Integer)

    Dim iDay As Integer = 1
    Dim TableID As Integer
    Dim TDCount As Integer = 0
    Dim FullTDCount As Integer = 0 '42
    Dim StringHtml As New StringBuilder
    Dim DaysInMonth As Integer = MonthDays
    clsWork.GetUnscheduledWork()
    Dim ClientName = "Terence Creighton" ' Test Replace with DB Value
    Dim JobName = "Install Job"

    ' Top structure of table
    StringHtml.Append("<table id='calendar' runatserver='server'>")
    StringHtml.Append("<tr class='weekdays'>")
    StringHtml.Append("<th scope='col'>Sunday</th>")
    StringHtml.Append("<th scope='col'>Monday</th>")
    StringHtml.Append("<th scope='col'>Tuesday</th>")
    StringHtml.Append("<th scope='col'>Wednesday</th>")
    StringHtml.Append("<th scope='col'>Thursday</th>")
    StringHtml.Append("<th scope='col'>Friday</th>")
    StringHtml.Append("<th scope='col'>Saturday</th>")
    StringHtml.Append("</tr>")


    StringHtml.Append("<tr Class='days'>")
    If Day > 1 Then

        Do While iDay < (Day)
            ' add Previous month style
            StringHtml.Append("<td  class='day other-month'>")
            StringHtml.Append("</td>")

            iDay = iDay + 1
            TDCount = TDCount + 1
            FullTDCount = FullTDCount + 1
        Loop

    End If

    For i As Integer = 1 To DaysInMonth

        If TDCount = 7 Then
            StringHtml.Append("</tr>")
            StringHtml.Append("<tr class='days'>")
            TDCount = 0
            FullTDCount = FullTDCount + 1
            i = i - 1
        Else
            StringHtml.Append("<td class='day' ")
            StringHtml.Append("id='")
            StringHtml.Append(i)
            StringHtml.Append("' Runat='server'>")
            StringHtml.Append("<div class='date'>")
            StringHtml.Append(i)
            StringHtml.Append("</div>")

            'StringHtml.Append("<div id='")
            'StringHtml.Append(i)
            'StringHtml.Append("' Runat='server'>")
            'StringHtml.Append("<div Class='panel panel-primary' draggable='true'>")
            'StringHtml.Append("<div Class='panel-heading'>")
            'StringHtml.Append(ClientName)
            'StringHtml.Append("</div>")
            'StringHtml.Append("<div Class='panel-body'>")
            'StringHtml.Append(JobName)
            'StringHtml.Append("</div>")
            'StringHtml.Append("</div>")

            StringHtml.Append("</div>")
            StringHtml.Append("</td>")
            TDCount = TDCount + 1
            FullTDCount = FullTDCount + 1
        End If

    Next

    StringHtml.Append("</tr>")
    StringHtml.Append("</table>")

    Return StringHtml.ToString

End Function

Public Sub ScheduledJobs()

    Dim StringHtml As New StringBuilder
    Dim ClientName As String
    Dim JobName As String
    Dim Work = clsWork.GetUnscheduledWork()


    For Each i As Integer In Work.Rows.Count
        ClientName = Work.Rows(i).Items("ClientName").ToString
        JobName = Work.Rows(i).Items("JobName").ToString
        ID = i.ToString
        StringHtml.Append("<div class='panel panel-primary' draggable='true' ondragstart='OnDragStart' ondrop='OnDrop' ")
        StringHtml.Append("id='")
        StringHtml.Append(ID)
        StringHtml.Append("'>")

        StringHtml.Append("<div class='panel-heading'>")
        StringHtml.Append(ClientName)
        StringHtml.Append("</div>")
        StringHtml.Append("<div class='panel-body'>")
        StringHtml.Append(JobName)
        StringHtml.Append("</div>")
    Next

    Dim MyTable As HtmlTable = Page.FindControl("calendar")
    Dim MyCell As HtmlTableCell
    MyCell.ID = "19"

    If MyCell Is Nothing Then
        messageResponse = "Tablecell not found"
    Else
        MyCell.InnerHtml = StringHtml.ToString

    End If

End Sub

Private Sub cmdLoadJobs_ServerClick(sender As Object, e As EventArgs) Handles cmdTry.ServerClick
    ScheduledJobs()
End Sub

我期待找到带有ID的td，并在("td元素“).innerhtml中添加html字符串。我尝试过各种findcontrol的组合，但结果都是空的。

Answer 1

您必须创建真正的动态控件。这里是一个关于如何与动态创建的表交互的非常基本的示例。

protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack == false)
    {
        //do not create dynamic control in an ispostback check
    }

    //create some table and it's rows and cells. note the assignent of an ID
    Table table = new Table()
    {
        ID = "MyTable1"
    };
    TableRow row = new TableRow()
    {
        ID = "MyRow1"
    };
    TableCell cell = new TableCell()
    {
        ID = "MyCell1",
        Text = "My 1st cell"
    };

    //add the cell to the row
    row.Controls.Add(cell);

    //add the row to the table
    table.Controls.Add(row);

    //add the table to the page
    PlaceHolder1.Controls.Add(table);
}


protected void Button1_Click(object sender, EventArgs e)
{
    //use findcontrol to locate the cell
    TableCell cell = PlaceHolder1.FindControl("MyCell1") as TableCell;

    //interact with it
    cell.Text = "Cell Found!";
}

Answer 2

我看到这个：

StringHtml.Append("<table id='calendar' runatserver='server'>")

虽然通过构建html字符串将原始html推到浏览器中的页面当然很好，但您不能以这种方式创建服务器控件。您将无法从后面的代码中访问html中的任何内容。runat='server'部分首先是键错误的，但是即使写得正确，也是毫无价值的。当您进入Page_Load事件时，寻找runat='server'属性的所有内容都已经完成了。