Change this code to do that whenever you press this button to add +1 qty in datagridview

Question

3.00/5 (2 votes)

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VB

Private Sub OK1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
 
    Dim sqlQRY As String = "SELECT * FROM Products WHERE ProductCode = '" & txtCode.Text & "'"
    Dim cmd As OleDbCommand = New OleDbCommand(sqlQRY, conn)
    Dim rdr As OleDbDataReader = cmd.ExecuteReader
 
    If txtCode.Text = "" Then
        MessageBox.Show("Input a product code!", "Warning!", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        txtCode.Text = ""
        txtCode.Focus()
    ElseIf rdr.HasRows Then
        rdr.Read()
 
        Dim intProductID As Integer = rdr("ProductID").ToString
 
        Dim newRow As SalesDataSet.SalesDetailsRow = SalesDataSet.SalesDetails.NewSalesDetailsRow
 
        newRow.SalesID = SalesIDTextBox.Text
        newRow.ProductName = intProductID
        newRow.Qty = 1
        Dim Price As Decimal = rdr("Price")
        newRow.Price = Price
        newRow.Amount = Price
 
        SalesDataSet.SalesDetails.Rows.Add(newRow)
 
        txtCode.Text = ""
        txtCode.Focus()
    Else
        MessageBox.Show("Product not found!", "Warning!", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
        txtCode.Text = ""
        txtCode.Focus()
    End If
 
    txtTotal.Text = Totals()
 
    Dim vat As Decimal
 
    vat = Val(txtTotal.Text) * 0.12
 
    txtVAT.Text = vat
    Button1.Enabled = True
 
End Sub

What I have tried:

I tried to to change " newRow.Qty = 1 " to " newRow.Qty += 1 " but not working !
Please help me for this code. Thanks ! :)

Posted 20-Jul-16 23:47pm

ionMEMBER

Updated 22-Jul-16 22:51pm

v2

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Comments

Richard MacCutchan 21-Jul-16 7:05am

You should get the initial quantity from your database record and then add 1 to it. Something like
newRow.Qty = rdr("Quantity").Value + 1;

ionMEMBER 21-Jul-16 7:25am

When I ok1.performclick() for two times then I show two rows in datagridview.
I want to show one row in datagridview when I click ok1.performclick() for two times but qty in one time is 1 and two times is 2. THANKS

Richard MacCutchan 21-Jul-16 7:35am

Then you need to change the program logic in your button click method. As it stands, you read a record, and create a new data row. You need to change it so it first checks for an existing row with that product id.

Richard Deeming 21-Jul-16 9:09am

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.

Everything you wanted to know about SQL injection (but were afraid to ask) | Troy Hunt[^]
How can I explain SQL injection without technical jargon? | Information Security Stack Exchange[^]
Query Parameterization Cheat Sheet | OWASP[^]

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khaled Ezzat Abdelfattah Abdelgawad · Accepted Answer · 2016-07-22T00:23:00

your code should update recor if reader has values and else inserts new record, so your code inside your btnAdd should be exactly as follows:

Dim sqlQRY As String = "SELECT * FROM Products WHERE ProductCode = '" & txtCode.Text & "'"
        Dim cmd As OleDbCommand = New OleDbCommand(sqlQRY, conn)
        Dim rdr As OleDbDataReader = cmd.ExecuteReader

        If rdr.HasRows Then
            rdr.Read()
            Dim r() As DataRow = SalesDataSet.SalesDetailsRow.Select("SalesID = " & rdr("SalesID"))
            r(0)("ProductName") = "exist22"
            r(0)("Qty") += 1
            r(0)("Price") = 10
            r(0)("Amount") = 10

        Else
            Dim newRow As SalesDataSet.SalesDetailsRow = SalesDataSet.SalesDetails.NewSalesDetailsRow
            newRow.SalesID = SalesIDTextBox.Text
            newRow.ProductName = intProductID
            newRow.Qty = 1
            newRow.Price = Price
            newRow.Amount = Price
            SalesDataSet.SalesDetails.Rows.Add(newRow)
            txtCode.Text = ""
            txtCode.Focus()
        End If
        SalesTableAdapter.Update(SalesDataSet)
        SalesDataSet.Worker.AcceptChanges()

khaled Ezzat Abdelfattah Abdelgawad · Accepted Answer · 2016-07-22T22:51:00

Dim r() As DataRow = SalesDataSet.SalesDetailsRow.Select("SalesID = " & rdr("SalesID"))

The previous code gets rows in the dataset that have the "SalesID" (primary Key) = SalesID retrieved by the reader (rdr("salesID")). And since this is Primary key so r() will get only one row. So r(0) is the only row in the r() collection as it's a zero based index. Finally , as follows you can update each field in this row (r(0)).

r(0)("ProductName") = "exist22"
r(0)("Qty") += 1
r(0)("Price") = 10
r(0)("Amount") = 10

If you still got problems please paste you code here again and state the problem.

Change this code to do that whenever you press this button to add +1 qty in datagridview

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