Download the Inventory.txt text file from the Homework Assignments folder for our class
I suggest you make a backup copy of the file
Create the form on the next page
ID is a combo box
Quantity change is a textbox. Integers can be positive or negative amount
The large box is a ListBox
Add a class (or can download clsInventory and include in project)
Create class-level variables for Product ID, Item Name, Quantity, and a separator
Create a constructor with a string argument (one line that was read from the text file)
Split the string and create properties for ID, Item Name, Quantity
Note: Quantity is an integer
Create a read-only property to set up the string used in the list box
Create a read-only property to set up the string used to write a line to the text file
Create a static method GetItems()
Set up a StreamReader
Create a collection list
Until end of stream: read a line, create a class object, add to the collection list
Close the stream
Return the collection list
Create a static method WriteItems()
Set up a StreamWriter
Use a ForEach to loop through the objects in the class-level collection list Write a line to the text file
Close the stream
In the form file:
The only class-level variable in the form file will be a collection list
In the Load event:
Fill the combo box with the item numbers
Fill the list box with data from the file
In the Update button click event:
If nothing is selected from the combo box display an error message
If the change quantity is empty, display an error message
If the change quantity cannot be converted (in a TryParse), display an error message
Use a ForEach to loop through the objects in the class-level collection list When the ID in the combo box matches the ID in the file, add the change amount to the Quantity property (unless that new quantity would be less than zero. If so, display an error message, clear the quantity text box, reset the focus, and return.)
Reset the DataSource and DisplayMember for the list box
Clear the text box and set the combo boxs selected index to -1
When the form opens, the combo box is filled and the files text is displayed in the list box
User can repeatedly select items from the combo box, enter a quantity change amount (positive numbers will increase the quantity, negative numbers will decrease the quantity), and click the Update button
Each time the Update Quantity button is clicked, the new collection is displayed in the list box
When the Exit button is clicked, the collection is written to the text file
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and should not be submitted as is. We are not held liable for any misuse of the solutions.
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