VB.Net Parameter count mismatch - vb.net

Question

I'm writing a function that convert an Array List into a Data Table, and I'm getting an error "Parameter count mismatch".
I've been looking and googling the issue but couldn't found anything that could help me resolve my issue.
```
'Function that convert ArrayList to DataTable
Public Function ConvertArrayListToDataTable(ByVal MyAList As ArrayList) As DataTable
Dim dt As New DataTable()
For i As Integer = 0 To MyAList.Count - 1
'create a Generic Object
Dim values As Object = MyAList.Item(i)
Dim properties() As PropertyInfo =
values.GetType().GetProperties()
'Loop through each property, and add it as a column to the datatable
For Each prop As PropertyInfo In properties
Try
Dim dc As DataColumn = New DataColumn(prop.Name)
'Add the column definition to the datatable
dc.DataType = prop.PropertyType
dt.Columns.Add(dc)
Catch ex As Exception
MessageBox.Show(" Can't add column" & ex.Message)
End Try
Next
'for each object in the list, loop through and add
'the data to the database
For Each o As Object In MyAList
Try
'create new row
Dim row As DataRow = dt.NewRow()
Dim pf() As PropertyInfo = o.GetType().GetProperties()
For Each item As PropertyInfo In pf
row(item.Name) = item.GetValue(o, Nothing)
Next
dt.Rows.Add(row)
Catch ex As Exception
MessageBox.Show(" Conversionerror" & ex.Message)
End Try
Next
Next
Return dt
End Function
```
I see the code get the Table and the column count as well, but cannot write value. it failed on getvalue.
The function suppose return a datatable containing retrieved data and populate datagrid
For Each prop As PropertyInfo In properties
Try
Dim dc As DataColumn = New DataColumn(prop.Name)
dc.DataType = prop.PropertyType
dt.Columns.Add(dc)
Catch ex As Exception
MessageBox.Show(" Can't add column" & ex.Message)
End Try
Next

Answer 1

If you are filling a DataTable from a database just let the DataTable figure out the datatype. ArrayList is not used in new code. You can make a class or structure and then use List(Of T) or if absolutely necessary List(Of Object). Test just the plain old DataTable.
Private Sub FillDataGridView()
Dim dt = New DataTable()
Using cn As New SqlConnection(My.Settings.CoffeeConnection)
Using cmd As New SqlCommand("Select * From Coffees;", cn)
cn.Open()
dt.Load(cmd.ExecuteReader)
End Using
End Using
For Each col As DataColumn In dt.Columns
Debug.Print(col.DataType.Name)
Next
DataGridView1.DataSource = dt
End Sub

Answer 2

Thank you Mary. It was a great experience. I was challenging myself to see how I can fill the Datagrid from Arraylist to Datatable. I finally follow your advice and review my Function as below:
Public Function FillDataGridView(SQLStatement As String) As DataTable
'create an DataTable to hold the results
Dim dt As New DataTable()
Try
Using con As New SqlConnection(ConnectionString)
con.Open()
Using cmd As New SqlCommand(SQLStatement, con)
'Get the reader
Using Reader = cmd.ExecuteReader()
dt.Load(Reader)
End Using
End Using
End Using
For Each col As DataColumn In dt.Columns
Debug.Print(col.DataType.Name)
Next
Catch ex As Exception
Console.WriteLine("SQL retrieve row:" & ex.Message & Err.Number)
Finally
Call CloseConn()
End Try
Return dt
End Function