Fastest way to update large data in Excel Table - vba

Question

I have a large table in Excel that has to be updated from a JSON source.
The data is fetched and available to me in the form of a dictionary after parsing the JSON.
I am iterating over all the fields in the data and updating relevant columns in a table.
Public Function GetFields(ByVal sApiEndpoint As String, ByVal sSheetName As String, ByVal sTableName As String)
.........
'Parse the Json Response and Update Table
Dim dicParsed As Dictionary
With ActiveWorkbook.Sheets(sSheetName).ListObjects(sTableName)
Dim iCount As Integer
iCount = 1
Set dicParsed = JsonConverter.ParseJson(sRestResponse)
For Each Item In dicParsed("data")
iCount = iCount + 1
Next Item
If .ListRows.Count >= 1 Then
.DataBodyRange.Delete
End If
Set Rng = .Range.Resize(iCount, .HeaderRowRange.Columns.Count)
.Resize Rng
Dim iRow As Integer
iRow = 0
For Each Item In dicParsed("data")
On Error Resume Next
.DataBodyRange.Cells(iRow, .ListColumns("name").Index) = Item("name")
.DataBodyRange.Cells(iRow, .ListColumns("id").Index) = Item("id")
.DataBodyRange.Cells(iRow, .ListColumns("type").Index) = Item("schema")("type")
iRow = iRow + 1
Next Item
End With
.........
End Function
It takes around 5 minutes to update a table of 500 rows with 15 columns with the calculations and updates turned off.
Is there any faster way to update the data in this scenario?

Answer 1

You can push the updates to an array and then bulk update the table.
Dim an array of any type without giving a size. Use Variant if you have columns of different type like numbers and strings.
ReDim the array when you know final dimensions.
Update the array with the data.
Set the tables databody equal to the array.
I was able to reduce update time from 5 minutes to less than 5 seconds with the below code.
Public Function GetFields(ByVal sApiEndpoint As String, ByVal sSheetName As String, ByVal sTableName As String)
.........
'Parse the Json Response and Update Table
Dim dicParsed As Dictionary
With ActiveWorkbook.Sheets(sSheetName).ListObjects(sTableName)
Dim iCount As Integer
Dim arrDataBuffer() As Variant
iCount = 1
Set dicParsed = JsonConverter.ParseJson(sRestResponse)
For Each Item In dicParsed("data")
iCount = iCount + 1
Next Item
If .ListRows.Count >= 1 Then
.DataBodyRange.Delete
End If
Set Rng = .Range.Resize(iCount, .HeaderRowRange.Columns.Count)
.Resize Rng
ReDim arrDataBuffer(iCount, .HeaderRowRange.Columns.Count)
Dim iRow As Integer
iRow = 0
For Each Item In dicParsed("data")
On Error Resume Next
arrDataBuffer(iRow, .ListColumns("name").Index - 1) = Item("name")
arrDataBuffer(iRow, .ListColumns("id").Index - 1) = Item("id")
arrDataBuffer(iRow, .ListColumns("type").Index - 1) = Item("schema")("type")
iRow = iRow + 1
Next Item
.DataBodyRange = arrDataBuffer
End With
.........
End Function