Is there a faster way to retrieve data from a table? - vb.net

Question

I have used this loop to display Data that graph using the Google Chart
The problem is that the graph contains a lot of data and it takes a long time to be made loaning
The question is whether there is a faster way to pass the data base?
dRow As Data.DataRow In xdata.Rows
If j = 0 Then
TempDate = Format(CDate(dRow.Item(0)), "dd/MM/yyyy")
MyXML += "[new Date(" & TempDate.Year & "," & TempDate.Month - 1 & ")"
j += 1
Else
TempDate = Format(CDate(dRow.Item(0)), "dd/MM/yyyy")
MyXML += ",[new Date(" & TempDate.Year & "," & TempDate.Month - 1 & ")"
j += 1
End If
For colIdx As Byte = 1 To xdata.Columns.Count - 1
If colIdx > 0 Then
If (dRow.Item(colIdx)).ToString <> Nothing Then
MyXML += "," & (dRow.Item(colIdx)).ToString
Else
MyXML += "," & "0"
End If
End If
`

Answer 1

You should be using a StringBuilder if you are going to be concatenating hundreds of strings. .NET strings are immutable which means each time they change, a new object has to be created.
Dim sb As New StringBuilder
For dRow As Data.DataRow In xdata.Rows
If j = 0 Then
TempDate = Format(CDate(dRow.Item(0)), "dd/MM/yyyy")
sb.Append("[new Date(" & TempDate.Year & "," & TempDate.Month - 1 & ")")
j += 1
Else
TempDate = Format(CDate(dRow.Item(0)), "dd/MM/yyyy")
sb.Append(",[new Date(" & TempDate.Year & "," & TempDate.Month - 1 & ")")
j += 1
End If
For colIdx As Byte = 1 To xdata.Columns.Count - 1
If colIdx > 0 Then
If (dRow.Item(colIdx)).ToString <> Nothing Then
sb.Append("," & (dRow.Item(colIdx)).ToString)
Else
sb.Append("," & "0")
End If
End If
Next
Next
And when you're done parsing the data:
Return sb.ToString