How to render PivotGrid component in SQL database with .NET WebForms?

''' Local Database Connection 
Public Class DbaseQuery
Public Function GetSQLResult()
Dim conSTR As String = "Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=" & AppDomain.CurrentDomain.BaseDirectory & "App_Data\Database1.mdf;Integrated Security=True"
Dim xquery As String = "SELECT * FROM table1"
Dim sqlConn As SqlConnection = New SqlConnection(conSTR)
sqlConn.Open()
Dim cmd As SqlCommand = New SqlCommand(xquery, sqlConn)
Dim da As SqlDataAdapter = New SqlDataAdapter(cmd)
Dim dt As DataTable = New DataTable()
da.Fill(dt)
For i = 0 To dt.Rows.Count - 1
 For j = 0 To dt.Rows(i).ItemArray.Length - 1
dt.Rows(i).ItemArray(j) = dt.Rows(i).ItemArray(j).ToString().Trim()
Next
Next
 
Return dt
End Function
End Class

Imports System.Data.SqlClient

Public Class RelationalGridController
Inherits ApiController
 
Dim dbquery As DbaseQuery = New DbaseQuery()
 
<System.Web.Http.ActionName("InitializeGrid")> _
<System.Web.Http.HttpPost> _
Public Function InitializeGrid(jsonResult As Dictionary(Of String, Object)) As Dictionary(Of String, Object)
 
//…
 
dict = htmlHelper.GetJsonData(jsonResult("action").ToString(), dbquery.GetSQLResult())
Return dict
End Function
 
<System.Web.Http.ActionName("FetchMembers")> _
<System.Web.Http.HttpPost> _
Public Function FetchMembers(jsonResult As Dictionary(Of String, Object)) As Dictionary(Of String, Object)
//…
dict = htmlHelper.GetJsonData(jsonResult("action").ToString(), dbquery.GetSQLResult(), jsonResult("headerTag").ToString(), jsonResult("sortedHeaders").ToString())
Return dict
End Function
 
//….