SQL Datatable error "Value cannot be null."

Question

I am executing a sql query, and I am getting an error Value cannot be null. Parameter name: dataTable

Code:

                strSQLHost = "select HostBase.AppName from HostBase where HostBase.appid=0" 
                Dim dtHost As DataTable
                Dim daHost As SqlDataAdapter = New SqlDataAdapter(strSQLHost, conn)
                daHost.Fill(dtHost)

The error occurs at the daHost.Fill(dtHost)
When I run this query in SQL Enterprise manager, I get a value of 'None'. It's a valid value, not a null value.

How can I resolve this?

Icarus · Accepted Answer · 2011-10-16 22:02:06Z

5

remove the last ' on your statement

I think it should read like this:

strSQLHost = "select Host.AppName from HostBase where HostBase.appid=0"

And instantiate your DataTable before passing it in:

Dim dtHost As DataTable = new DataTable()

edited Oct 16, 2011 at 22:02

answered Oct 16, 2011 at 21:56

Icarus

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4 Comments

JeffO Over a year ago

Wouldn't it just turn the rest of the line into a comment?

Frank Over a year ago

lcarus, that is a comment line. I did remove it, but no luck

Icarus Over a year ago

@JeffO OP updated his question. He had a ' right after appid=0 and I thought he meant to concatenate the output of dmRow("appid") or something like that he had written initially

Frank Over a year ago

Dim dtHost As DataTable = new DataTable() was the answer. Thanks very much lcarus !!!

JeffO · Accepted Answer · 2011-10-16 21:57:41Z

1

select Host.AppName from HostBase where HostBase.appid=0

Seems like you're mixing table names when you only refer to one table: HostBase. You can't use table: Host in this query without including it in some sort of join (Even if it turned into a Cartesian Product) This is the change.

select HostBase.AppName from HostBase where HostBase.appid=0

Put a break and see the exact value of the string variable: strSQLHost

answered Oct 16, 2011 at 21:57

JeffO

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1 Comment

Frank Over a year ago

sorry... that was a typo on my part in the original posting

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