为数据表分配TVP值

Question

I have had an issue I have after much stress, narrowed down to assigning a string to a datatable (cell?)

Dim dc As New DataColumn("Col1")
dc.DataType = System.Type.GetType("System.String")
ParameterTable.Columns.Add(dc)

For i = 0 To whereInValues.Count - 1
                r = ParameterTable.NewRow
                r.Item("Col1") = whereInValues(i).ToString
                ParameterTable.Rows.Add(r)

Next

This is a small snippet of the code in question. It's a loop iterating through the whereInValues List(Of String) containing strings for the IN() values of an SQL Statement.

ParameterTable is my DataTable

This is assigned to the .value property of the parameter, which is set to Structured.

Basically, when I set to the value of the datatable using the .ToString method of the List, it shows fine in the debugger, but doesn't return any results from the database. When I set the value directly like:

r.Item(column) = "Barratt Homes"

It returns the correct results. I have tried wrapped a CStr() around the expression, but to no effect.

What is the difference between assigning the datatable value this way? Is .ToString to same as a System.String?

Answer 1

Sorry, I have found the answer to my question.

My code was automatically wrapping the strings of the List(Of String) with a ' character. When using parameters you obviously doesn't need that as it forms part of the string you are searching for. So when I was assign the string manually, I didn't have these characters there.

Stupid mistake...