Pass single column of dataTable to function in vb.net-CodePudding

I have a dataTable with 5 rows and 2 columns(Id,Name). I need to pass only one column of the dataTable to a function parameter which is a dataTable.

This is what I tried

myfunction(dt.Rows.Item("Id")

Public function myfunction (dt as dataTable)
// Some code

End Function

But this is not working. Why is it so? Even if a column is excluded the dataTable still remains as a dataTable. How can I pass the "ID" column without including the "Name" column to this function as a parameter.

CodePudding user response：

There are several issues with what you provided.

First, your function call is missing a parentheses on the end.

myfunction(dt.Rows.Item("Id"))

Second, your function is expecting a datatable, but you are passing a cell (and also not specifying which row, so this wouldn't work)...

If you truly want your function to use a datatable, you need to just pass dt like:

myFunction(dt)

If you want to pass the cell value instead, you can change your function definition to take a string or whatever datatype is within that column, and pass the value like:

myFunction(dt.Rows(ROWNUMBER).Item("Id"))

CodePudding user response：

Functions need a DataType and a Return statement.

Your Function is expecting a DataTable and you are passing a DataRow.

dt.Rows.Item takes a Integer, not a String.

You don't Dim a Function, you call it.

Stack Overflow asks for a Minimum, Complete and Reproducible example of your problem. Your code is not that.

I gave your Function a name and something trivial to do so I could demonstrate the proper syntax. If you don't need the whole DataTable then don't pass it to the function. I am just passing the values in the ID column as a List(Of T) If your Function is not under your control and it wants a DataTable, then just pass dt.

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim lst = dt.Rows.OfType(Of DataRow)().Select(Function(dr) dr.Field(Of Integer)("ID")).ToList()
    Dim MaxID = GetMaxID(lst)
End Sub

Public Function GetMaxID(lst As List(Of Integer)) As Integer
    Dim MaxI = lst.Max
    Return MaxI
End Function