Object variable Block variable not set

[alexbob18]

Hi. I'm working in a VB.NET project. My problem is in my project i've created a
class clsdatabase where all the connection and executing the query is done. But when i run program the insert and update query runs few times and
later without any change of coding i get "Object variable Block variable not set".

I get this error in the following code..

dim DbObj = New ClsDatabase
DbObj.ExecuteQuery("Here is the update query")

inside the class clsdatabase

Public Sub ExecuteQuery(ByVal strSql As String)
        Dim cmd As SqlCommand
        If sqlQryCon.State = ConnectionState.Open Then sqlQryCon.Close()
        cmd = New SqlCommand(strSql, sqlQryCon)
        sqlQryCon.Open()
        cmd.ExecuteNonQuery()
        sqlQryCon.Close()
    End Sub

Why it's happening like this? Please help me rectify this problem. It's making
the whole program not run. Thank u for u'r help in advance.

 

[giadich]

where are you declaring and instancing sqlQryCon?

 

[alexbob18]

Public sqlQryCon As SqlConnection

Public Sub New()
MyBase.New()
sqlQryCon = New SqlConnection(strCon)
End Sub

strCon = I give the connection string

I'm doing this inside the ClsDatabase

 

[mentalhard]

Please check these two articles:

http://msdn2.microsoft.com/en-us/library/5szkzs17(VS.80).aspx
http://support.microsoft.com/kb/316478

HTH