ASP.NET Expression is not a method

I'm ge开发者_JS百科tting a build error, "Expression is not a method" for the following code

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
          'LOOKUP SKU DATA ON BLUR
          Dim lookup As String = ClientScript.GetPostBackEventReference(txtSKU, "", False)
          txtSKU.Attributes.Add("onblur", "doLookup()")

          If Not IsPostBack Then
               If txtSKU.Text <> "" Then
                    lookup() '*************the error points to this line*******
               End If
          End If

     End Sub

     Protected Sub btnLookup_Command(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs) Handles btnLookup.Command
          lookup()
     End Sub

     Protected Sub lookup()
          'BLAH BLAH BLAH
     End Sub

Any thoughts or suggestions?

It's because you've declared a local variable with the same name in the method:

Dim lookup As String = ClientScript.GetPostBackEventReference(txtSKU, "", False)

In short, don't do that :) Simply rename the variable and it should be fine.

you have declared lookup string within the same method and also lookup function.

Change name of your string and it will work.