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Apr 10th, 2008

Object reference not set to an instance of an object.

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Im getting a NullReferenceException when I goto add a product to my cart, i get the error when i come to this part

ASP.NET Syntax (Toggle Plain Text)
cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)
cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)

I use extremely similar code in another one of my projects and do not come across this problem, I have also researched it for a while and still came across no soltuion.

ASP.NET Syntax (Toggle Plain Text)
Protected Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
 
        Dim cart As New Cart
        cart = Session("Cart")
 
 
        Dim flag As Integer = 1
        Dim finishColor As String = ""
        Dim knobColor As String = ""
        Dim prodQty As Integer = 0
        Dim price As Decimal = 0
        Dim name As String = ""
        Dim productnumber As Integer = 0
 
        If txtQty.Text <> "" And IsNumeric(txtQty.Text) Then
            prodQty = txtQty.Text
            flag = 0
        Else
            lblError.Text = "Please enter a numeric quantity."
            Return
        End If
 
        productnumber = prodID
        name = lblName.Text
        price = lblPrice.Text
        prodQty = txtQty.Text
        finishColor = DDFinish.SelectedItem.Text
        knobColor = DDKnob.SelectedItem.Text
 
 
 
        cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)
 
 
        Session("Cart") = cart
Protected Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click

        Dim cart As New Cart
        cart = Session("Cart")


        Dim flag As Integer = 1
        Dim finishColor As String = ""
        Dim knobColor As String = ""
        Dim prodQty As Integer = 0
        Dim price As Decimal = 0
        Dim name As String = ""
        Dim productnumber As Integer = 0

        If txtQty.Text <> "" And IsNumeric(txtQty.Text) Then
            prodQty = txtQty.Text
            flag = 0
        Else
            lblError.Text = "Please enter a numeric quantity."
            Return
        End If

        productnumber = prodID
        name = lblName.Text
        price = lblPrice.Text
        prodQty = txtQty.Text
        finishColor = DDFinish.SelectedItem.Text
        knobColor = DDKnob.SelectedItem.Text



        cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)


        Session("Cart") = cart

Any help is appreciated!

firebirds98

Reputation Points: 10

Solved Threads: 0

Newbie Poster

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15 posts
since Feb 2008

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Apr 11th, 2008

Re: Object reference not set to an instance of an object.

Something is returning a returning noting as a value.... try running it on the VS test server and see where it breaks, look at the data within the string... you will see it is "" (null). you may need to change the .text to .text.tostring

ericstenson

Team Colleague

Reputation Points: 14

Solved Threads: 29

Posting Whiz in Training

Offline

293 posts
since Dec 2007

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Apr 11th, 2008

Re: Object reference not set to an instance of an object.

This error occurs when you don't use the "New" keyword to instantiate the Object. Your code should be either of the following 2:
Dim cart as New Cart
OR
Dim cart as Cart
cart = New Cart

Regards
Sunil Punjabi

sierrasoft

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

31 posts
since Nov 2006

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Apr 11th, 2008

Re: Object reference not set to an instance of an object.

Session("Cart") is null
So either check if Session("Cart") is null, and create a new one if it doesnt exists. or create a new Session("Cart") when the session is started.

Session("Cart") = New Cart

plazmo

Reputation Points: 23

Solved Threads: 16

Posting Whiz in Training

Offline

206 posts
since Aug 2005

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Apr 11th, 2008

Re: Object reference not set to an instance of an object.

Session("Cart") is not initialized yet. So make sure You need to check Session("Cart") with null(nothing) and assign it properly. You need to do something like this.

Dim cart As New Cart
cart = Session("Cart")
if (cart == Nothing)
cart = new cart();

then use cart object. you won't get this type of error.

Click to Expand / Collapse Quote originally posted by firebirds98 ...

Im getting a NullReferenceException when I goto add a product to my cart, i get the error when i come to this part
ASP.NET Syntax (Toggle Plain Text)
cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)
cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)
I use extremely similar code in another one of my projects and do not come across this problem, I have also researched it for a while and still came across no soltuion.
ASP.NET Syntax (Toggle Plain Text)
Protected Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
 
        Dim cart As New Cart
        cart = Session("Cart")
 
 
        Dim flag As Integer = 1
        Dim finishColor As String = ""
        Dim knobColor As String = ""
        Dim prodQty As Integer = 0
        Dim price As Decimal = 0
        Dim name As String = ""
        Dim productnumber As Integer = 0
 
        If txtQty.Text <> "" And IsNumeric(txtQty.Text) Then
            prodQty = txtQty.Text
            flag = 0
        Else
            lblError.Text = "Please enter a numeric quantity."
            Return
        End If
 
        productnumber = prodID
        name = lblName.Text
        price = lblPrice.Text
        prodQty = txtQty.Text
        finishColor = DDFinish.SelectedItem.Text
        knobColor = DDKnob.SelectedItem.Text
 
 
 
        cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor)
 
 
        Session("Cart") = cart
Protected Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click Dim cart As New Cart cart = Session("Cart") Dim flag As Integer = 1 Dim finishColor As String = "" Dim knobColor As String = "" Dim prodQty As Integer = 0 Dim price As Decimal = 0 Dim name As String = "" Dim productnumber As Integer = 0 If txtQty.Text <> "" And IsNumeric(txtQty.Text) Then prodQty = txtQty.Text flag = 0 Else lblError.Text = "Please enter a numeric quantity." Return End If productnumber = prodID name = lblName.Text price = lblPrice.Text prodQty = txtQty.Text finishColor = DDFinish.SelectedItem.Text knobColor = DDKnob.SelectedItem.Text cart.AddProduct(productnumber, name, price, prodQty, knobColor, finishColor) Session("Cart") = cart
Any help is appreciated!

harivb

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

3 posts
since Apr 2008

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

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