Error when running code snippet in vb.net using max of data column in SQL Server.

Question

User-467962651 posted

Hi here is code snippet used temprarily on button to debug. This works but i wish to use the 2nd snippet.

1st snippet

Dim connString As New SqlConnection

connString.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings("sql2008r2_857000_dmcsqlConnectionString").ConnectionString

Dim cmd As New SqlCommand("select TOP 1 no from members ORDER BY no DESC", connString)

Dim reader As SqlDataReader

Dim lastNumber As String

Using (connString)

connString.Open()

reader = cmd.ExecuteReader()

While reader.Read

lastNumber = reader.Item("no")

End While

End Using

Response.Write(lastNumber)

2nd snippet

Dim connString As New SqlConnection

connString.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings("sql2008r2_857000_dmcsqlConnectionString").ConnectionString

Dim cmd As New SqlCommand("select max(no) from members ", connString)

Dim reader As SqlDataReader

Dim lastNumber As String

Using (connString)

connString.Open()

reader = cmd.ExecuteReader()

While reader.Read

lastNumber = reader.Item("no")

End While

End Using

Response.Write(lastNumber)

1. This gives error: System.IndexOutOfRangeException: 'no' on line in bold
3. no is a column name which has nvarchar(8) data type and allows nulls
5. Any help would be welomed

Answer 1

User1120430333 posted

I don't where you came up with reader.item, becuase it is not right.

https://www.dotnetheaven.com/article/read-the-data-with-the-datareader-object-in-vb.net

Answer 2

User-467962651 posted

Hi

Now fixed thanks that link you gave pointed me in the right direction.

I then had a problem with the max function then realised it must be given an alias in sql so it i chose max(no) as number.

So thanks once again.