SQL Data To Populate Graph?

I have created a function to create a string to populate a y axis with data:

Function talktosql() As Double
Dim ConnString As String = "Data Source=MARK-WORKMSSMLBIZ;Initial Catalog=Yahoo_data;Integrated Security=True"
Dim SQLString As String = "SELECT [RDSA.L] FROM yahoo_data.dbo.XLON"
Dim SqlDataAdapter1 As New SqlDataAdapter(SQLString, ConnString)

[code]....

so it should for example come out like this:

Dim yValues As Double() = {55.62, 45.54, 73.45, 9.73, 88.42, 45.9, 63.6, 85.1, 67.2, 23.6}

I cannot seem to get the data from the function into the right format to populate "yvalues".(the msgbox that I put in at the end in the first code renders the result "0")