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Views: 617 | Replies: 4
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Join Date: Feb 2008
Posts: 8
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Newbie Poster
Im getting a NullReferenceException when I goto add a product to my cart, i get the error when i come to this part
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.
Any help is appreciated!
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.
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
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Join Date: Dec 2007
Posts: 286
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Posting Whiz in Training
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."
"Dummy."
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Join Date: Nov 2006
Location: Nasik-India
Posts: 21
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Rep Power: 2
Solved Threads: 0
Newbie Poster
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
Dim cart as New Cart
OR
Dim cart as Cart
cart = New Cart
Regards
Sunil Punjabi
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Join Date: Aug 2005
Location: Ohio
Posts: 204
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Solved Threads: 16
Posting Whiz in Training
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
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
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Newbie Poster
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.
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
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.
Any help is appreciated!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
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