putting array from vb codebehind into javascript datatable

问题

So I'm trying to use this javascript with my asp.net website https://google-developers.appspot.com/chart/interactive/docs/gallery/linechart

I have an array in codebehind that has my data which i converted to a multidimensional datatable like this.

<in codebehind vb>
Public Property datat As DataTable

For outerIndex As Integer = 0 To 2
    Dim newRow As DataRow = table.NewRow()
    For innerIndex As Integer = 0 To 2
            newRow(innerIndex) = Array(outerIndex, innerIndex)
    Next
    table.Rows.Add(newRow)
Next

datat = table

<in asp>

function drawChart() {
    var data = <%=datat%>

I always get an error datatable not defined.

My new work

<in asp>

<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">
    google.load("visualization", "1", {packages:["corechart"]});
    google.setOnLoadCallback(drawcharts);
    function drawcharts() {
        var data = google.visualization.arrayToDataTable([
            ['X', 'MW'],
      [<%=mwtimepublic%>, <%=mwarraypublic%>]
        ]);

        var options = {
            title: 'MW Trend'
        };

        var chart = new google.visualization.LineChart(document.getElementById('chart_div'));
        chart.draw(data, options);
    });
</script>

Public Function Dtable() As DataTable Dim startdate As String Dim enddate As String

    If FirstRun = False Then
        datat.Clear()
    End If

    If FirstRun = True Then
        FirstRun = False
        enddate = Date.Today
        startdate = DateAdd(DateInterval.Day, -20, Date.Today)
    Else
        enddate = TextBox2.Text
        startdate = TextBox1.Text
    End If

'<confidential code></confidentialcode>

    Dim mwaray(pdata.Count)
    Dim mwtime(pdata.Count)
    Dim table As New DataTable
    table.Columns.Add("X")
    table.Columns.Add("MW")
    Dim i As Integer
    Dim x As Integer
    For i = 1 To pdata.Count
        mwaray(i) = pdata(i).Value
        If mwaray(i) > upperlimit Then
            upperlimit = mwaray(i) + 50
        End If
    Next

    For i = 1 To pdata.Count
        mwtime(i) = "'" & pdata(i).TimeStamp.LocalDate.Month.ToString() & "/" & pdata(i).TimeStamp.LocalDate.Day.ToString() & "/" & pdata(i).TimeStamp.LocalDate.Year.ToString() & " " & pdata(i).TimeStamp.LocalDate.TimeOfDay.Hours.ToString() & ":" & pdata(i).TimeStamp.LocalDate.TimeOfDay.Minutes.ToString() & ":" & pdata(i).TimeStamp.LocalDate.TimeOfDay.Seconds.ToString() & "'"
    Next

    For i = 1 To pdata.Count
        mwarraypublic.Add(mwaray(i))
    Next

    For i = 1 To pdata.Count
        mwtimepublic.Add(mwtime(i))
    Next

End Function

I'm still not getting the chart to draw

回答1:

I made a video on how to create a jquery ui autocomplete while getting an array to javascript from codebehind

skip to 6:00 to see how I made the array http://www.youtube.com/watch?v=ULHSqoDHP-U&list=UUgtKyNvllU9E6c2Mi8OtzCQ&index=6&feature=plcp

PageMethods.YourWebMethod(function(results){
  var data = resluts;
  //the rest of your code goes here...
});

update:

Google actually converts an array of arrays into a datatable. In other words, you have to return an array of rows, and the rows them self are an array of column values.

So in you code behind you do the following first import webservices

Imports System.Web.Services

then create your webmethod with a function that returns an arraylist

<WebMethod()>
Public Shared Function Dtable() As ArrayList
dim table As New ArrayList
Dim YourDataSetTable as new Dataset.YorDataTable
'fill you table here

'first get column names as the first row/array
dim colNames as New ArrayList

For Each col as DataColumn in YourDataSetTable.Columns
   colNames.Add(col.ColumnName)
Next
table.Add(colNames)

'then on to the data
For Each r as DataRow in YourDataSetTable .Rows
  dim colVals as New ArrayList
  For Each col as DataColumn in YourDataSetTable.Columns
    colVals.Add(r.Item(col.ColumnName))
  Next
  table.Add(colVals)
Next
Return table
End Function

Then in javascript

PageMethods.Dtable(function(results){
  var data = resluts;
  //the rest of your code goes here...
});

make sure you have a script manager on the page with pagemethods enabled.

回答2:

The code sample you posted should not compile. In Visual Basic there are auto-implemented properties which is what it looks you have on the first line of your code, followed by a block that has nothing to do with the data table.

Try putting the code into your properties getter:

Public ReadOnly Property datat As DataTable
   Get
      For outerIndex As Integer = 0 To 2
          Dim newRow As DataRow = table.NewRow()

          For innerIndex As Integer = 0 To 2
              newRow(innerIndex) = Array(outerIndex, innerIndex)
          Next

          table.Rows.Add(newRow)
      Next

      Return table
   End Get
End Property

来源：https://stackoverflow.com/questions/13333664/putting-array-from-vb-codebehind-into-javascript-datatable

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arrays

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