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Passing SQL stored procedure output parameter to ASP.net (VB)

I am working with SQL output parameters for the first time, and I'm running into some difficulty.  It's in a stored procedure for an ASP.net (VB) website.

Here is the error message I'm getting at Line 15:

"System.NullReferenceException was unhandled by user code"
Message="Object reference not set to an instance of an object."

If someone is able to review my code and see if they can spot my error, it would be greatly appreciated.




   
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim conSQL As New SqlConnection(strSQLConnection)
        conSQL.Open()

        Dim cmdSQL As New SqlCommand("sp_inventory", conSQL)
        cmdSQL.CommandType = CommandType.StoredProcedure

        Dim paramResult As New SqlParameter
        paramResult.ParameterName = "@TotalUnit1"
        paramResult.Direction = ParameterDirection.Output
        cmdSQL.Parameters.Add(paramResult)


       
        Literal1.Text = cmdSQL.Parameters("@TotalUnit1").Value.ToString


        cmdSQL.ExecuteNonQuery()

        conSQL.Close()
    End Sub

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Alter PROCEDURE [dbo].[sp_inventory]


@TotalUnit1 int OUTPUT

AS

Begin

Select @TotalUnit1 = SUM(Quantity)
From Table1
Where (Condition1 = '1') AND (Condition2 = '2') 
	
END

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0
Jorhal
Asked:
Jorhal
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1 Solution
 
Om PrakashCommented:
replace

cmdSQL.ExecuteNonQuery()
Literal1.Text = cmdSQL.Parameters("@TotalUnit1").Value.ToString

with

cmdSQL.ExecuteNonQuery()
Literal1.Text = cmdSQL.Parameters("@TotalUnit1").Value.ToString

please check the following example as well...
http://www.4guysfromrolla.com/articles/062905-1.aspx
0
 
Om PrakashCommented:
i mean call cmdSQL.ExecuteNonQuery() first and then retreive the value..
0
 
Mohit VijayCommented:



Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim conSQL As New SqlConnection(strSQLConnection)
        conSQL.Open()

        Dim cmdSQL As New SqlCommand("sp_inventory", conSQL)
        cmdSQL.CommandType = CommandType.StoredProcedure

        Dim paramResult As New SqlParameter
        paramResult.ParameterName = "@TotalUnit1"
        paramResult.Direction = ParameterDirection.Output
        cmdSQL.Parameters.Add(paramResult)

cmdSQL.ExecuteNonQuery()
       
        Literal1.Text = paramResult.Value.ToString


                conSQL.Close()

conSQL.dispose()
    End Sub

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0
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Mohit VijayCommented:

Alter PROCEDURE [dbo].[sp_inventory]


@TotalUnit1 int OUTPUT

AS

Begin

Select @TotalUnit1 = SUM(Quantity)
From Table1
Where (Condition1 = '1') AND (Condition2 = '2')

Return  @TotalUnit1
	
END

Open in new window

0
 
JorhalAuthor Commented:
Thanks for the responses.  Made the change to call cmdSQL.ExecuteNonQuery() first.  However, cmdSQL.ExecuteNonQuery() now gets the following error:

[InvalidOperationException: String[0]: the Size property has an invalid size of 0.]
 
0
 
Mohit VijayCommented:
Dim paramResult As New SqlParameter
        paramResult.ParameterName = "@TotalUnit1"
        paramResult.Direction = ParameterDirection.Output
        cmdSQL.Parameters.Add(paramResult)


define the type of output parameter, by default it is taking it as varchar, that need size to be set, you have to define it as int, same as stored procedure that you are using.
0
 
Mohit VijayCommented:
paramResult.DbType = DbType.Int32
0
 
Mohit VijayCommented:
replace with
Dim paramResult As New SqlParameter
        paramResult.ParameterName = "@TotalUnit1"
paramResult.DbType = DbType.Int32
        paramResult.Direction = ParameterDirection.Output
        cmdSQL.Parameters.Add(paramResult)

Open in new window

0
 
JorhalAuthor Commented:
Works perfectly -- Thanks!
0
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