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Object reference not set to an instance of an object.

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Join Date: Feb 2008

Posts: 13

Reputation: firebirds98 is an unknown quantity at this point

Solved Threads: 0

firebirds98 firebirds98 is offline

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Newbie Poster

Object reference not set to an instance of an object.

Apr 10th, 2008

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

 Help with Code Tags 
 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.

 Help with Code Tags 
 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!

•

Join Date: Dec 2007

Posts: 291

Reputation: ericstenson is an unknown quantity at this point

Solved Threads: 29

ericstenson ericstenson is offline

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Posting Whiz in Training

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

Apr 11th, 2008

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

--
"Dummy."

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Join Date: Nov 2006

Posts: 32

Reputation: sierrasoft is an unknown quantity at this point

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sierrasoft sierrasoft is offline

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Light Poster

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

Apr 11th, 2008

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

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Join Date: Aug 2005

Posts: 206

Reputation: plazmo is an unknown quantity at this point

Solved Threads: 16

plazmo

Offline

Posting Whiz in Training

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

Apr 11th, 2008

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

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Join Date: Apr 2008

Posts: 3

Reputation: harivb is an unknown quantity at this point

Solved Threads: 0

harivb

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Newbie Poster

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

Apr 11th, 2008

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.

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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
Help with Code Tags

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.
Help with Code Tags

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!