Index was outside the bounds of the array vending machine

Question

1.00/5 (1 vote)

See more:

So I am programming a vending machine and the query is for a button to select a product from the vending machine, any help is appreciated. Price, products and productid are all part of the database.

C#

private void runQurey(String query)
       {
           OleDbCommand cmd = new OleDbCommand(query, conn);
           OleDbDataReader cusReader = cmd.ExecuteReader();

           lblprice.Text = "";
           lblquantity.Text = "";

           while (cusReader.Read())
           {
               lblprice.Text = cusReader.GetValue(0).ToString();
               lblquantity.Text = cusReader.GetValue(1).ToString();
           }
       }

       private void btnselect1_Click(object sender, EventArgs e)
       {
           runQurey("SELECT Price FROM Products WHERE ProductID = 1");

       }

Posted 14-Oct-14 21:27pm

Member 11154485

Updated 14-Oct-14 21:38pm

CPallini

v2

Add a Solution

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2014-10-14T21:36:00

Solution 1

Well...you are requesting one column from your DB:

C#

runQurey("SELECT Price FROM Products WHERE ProductID = 1");

And then trying to process two columns:

C#

lblprice.Text = cusReader.GetValue(0).ToString();
lblquantity.Text = cusReader.GetValue(1).ToString();

I suspect you want to return more columns, so try something like:

C#

runQurey("SELECT Price, Quantity FROM Products WHERE ProductID = 1");

Posted 14-Oct-14 21:36pm

OriginalGriff

Comments

CPallini 15-Oct-14 3:38am

5.

Member 11154485 15-Oct-14 3:53am

Well I did what you told me too, except now I get an error for this:
private void runQurey(String query)
{
OleDbCommand cmd = new OleDbCommand(query, conn);
OleDbDataReader cusReader = cmd.ExecuteReader(); <----------

It says "No value given for one or more required parameters"

BTW I am really new to this, I don't even know most of this, I am extremely sorry for the hassle as I am a really really new newbie

OriginalGriff 15-Oct-14 4:01am

"No value given for one or more required parameters"
Means you typed it wrong! :laugh:
Check the runQuery line and make sure you know exactly what is in the string you are passing to sql: chances are you typed a "@" in there somewhere.
If you can't see it, paste your code fragment here.

Member 11154485 15-Oct-14 4:47am

help me plzzzz i can't find :'(

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;

namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
OleDbConnection conn = new OleDbConnection();
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
conn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source="
+ "D:\\akhan38\\My Documents\\School\\IPT\\VendingMachine.accdb;");

try
{
conn.Open();
}
catch (Exception ex)
{
MessageBox.Show("Failed to connect to data source");
}
}
public double money;

private void button14_Click(object sender, EventArgs e)
{
money = money + 5.00;
label1.Text = money.ToString();
}

private void button15_Click(object sender, EventArgs e)
{
money = money + 10.00;
label1.Text = money.ToString();
}

private void btnvalue1_Click_1(object sender, EventArgs e)
{
money = money + 1.00;
label1.Text = money.ToString();
}

private void btnvalue2_Click(object sender, EventArgs e)
{
money = money + 2.00;
label1.Text = money.ToString();
}

private void runQurey(String query)
{
OleDbCommand cmd = new OleDbCommand(query, conn);
OleDbDataReader cusReader = cmd.ExecuteReader();

lblprice.Text = "";
lblquantity.Text = "";

while (cusReader.Read())
{
lblprice.Text = cusReader.GetValue(0).ToString();
lblquantity.Text = cusReader.GetValue(1).ToString();
}
}

private void btnselect1_Click(object sender, EventArgs e)
{
runQurey("SELECT Price FROM Products WHERE ProductID = 1");

}
}
}

OriginalGriff 15-Oct-14 4:58am

That's your original, unmodified code: it still reads one column (Price) from your Products table and tried to access two different values per row (Price and Quantity).
Check your column names in the DB, and make the change exactly as I show above.

Member 11154485 15-Oct-14 5:14am

But my productsinstock (quantity) is a different table from price in my DB, how do I make it so that it grabs two values in the same line of code? Or is that now even possible?.

OriginalGriff 15-Oct-14 5:19am

Why is it in a different table?

You can do it, it's not that difficult:
SELECT p.Price, q.Quantity FROM Products p JOIN QuantitityTableName q ON p.ProductID=q.ProductID WHERE p.ProductID=1
But that is a bit advanced if you aren't sure yet how to get values in the first place! :laugh:

The chances are that for this exercise, you shouldn't keep prices and stock levels in separate tables, unless you have a very good reason (and I can think of some, but they are unlikely to be applicable to a "teaching" exercise as I assume this is).

Member 11154485 15-Oct-14 5:21am

I mean column, sorry if I am annoying you :(

OriginalGriff 15-Oct-14 5:34am

No, I'm difficult to annoy! :laugh:
OK, if the two columns are both in the same table, then you can return them together exactly as I showed originally:

SELECT Price, Quantity FROM Products WHERE ProductID=1

That returns two columns of data for each row that matches in the table, and your code here:

lblprice.Text = cusReader.GetValue(0).ToString();
lblquantity.Text = cusReader.GetValue(1).ToString();

should work fine.

But...you are making problems for yourself in future: the two methods (btnselect1_Click and runQurey) are very "tied together" in that you can't change one without considering the effects on the other. And you can't really use the runQurey method for anything else, because it expects the query you pass it to be a SELECT query, and return two columns. You might want to re-think that bit later, when you have it working.

Member 11154485 15-Oct-14 6:02am

okay cool, 1 question, where you shows "quantity" in front of price, does that mean that is the column name?

OriginalGriff 15-Oct-14 7:42am

After price, not before - columns are returned in the exact order you specify (or the numeric indexing wouldn't work).

The general format is:

SELECT commaseparatedlistofcolumns FROM tablename WHERE condition

OriginalGriff 15-Oct-14 5:20am

Note change to JOIN code: I got the ID column name wrong in the WHERE clause :blush:

Rajesh waran · Answer 2 · 2014-10-14T21:38:00

Solution 2

your query is not correct,bcoz u didn't take quantity value from ur table but u r bindinding quantity value from reader .Ur datareader is holding only price alone not quantity value

Posted 14-Oct-14 21:38pm

Rajesh waran

Nihar Ranjan Sahu · Answer 3 · 2014-10-14T22:00:00

Solution 3

Your query is not right.Add 2 columns name if you want two value in select query.

Posted 14-Oct-14 22:00pm

Nihar Ranjan Sahu