Hi I'm A Beginner, And I Got This Error I Don't Know What's Wrong Anyone Can Help Me Please

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VB

Private Sub BtnDelete_Click(sender As System.Object, e As System.EventArgs) Handles BtnDelete.Click
        If MessageBox.Show("Are you sure?", "Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) = Windows.Forms.DialogResult.Yes Then
            cnsql = "delete TbProduct where ProductID= "" & ProductID & """
            cn = New SqlClient.SqlConnection(cnstr)
            cn.Open()
            cm = New SqlClient.SqlCommand(cnsql, cn)
            dr = cm.ExecuteReader <----Error! it says Invalid column name ' & ProductID & '.
            ShowData()
            TxtProductNameD.Clear()
            TxtProductpriceD.Clear()
            BtnDelete.Enabled = False
        Else
            TxtProductNameD.Clear()
            TxtProductpriceD.Clear()
            BtnDelete.Enabled = False

        End If
    End Sub

[edit]Code block added - OriginalGriff[/edit]

Posted 17-Jan-15 2:13am

Member 11381884

Updated 17-Jan-15 2:28am

OriginalGriff

v2

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Idle_Force 17-Jan-15 11:02am

Why do we allow bad question titles - these are not searchable by any means.

2 solutions

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DamithSL · Accepted Answer · 2015-01-17T02:29:00

Solution 1

Use parameter as below

C#

cnsql = "delete from TbProduct where ProductID=@ProductID"
cn = New SqlClient.SqlConnection(cnstr)
cn.Open()
cm = New SqlClient.SqlCommand(cnsql,cn)
cm.Parameters.AddWithValue("@ProductID",ProductID)
dr = cm.ExecuteReader

Posted 17-Jan-15 2:29am

DamithSL

Updated 17-Jan-15 2:40am

v2

Comments

Member 11381884 17-Jan-15 10:16am

Thanks :D

OriginalGriff · Accepted Answer · 2015-01-17T02:32:00

VB

cnsql = "delete TbProduct where ProductID= "" & ProductID & """
cn = New SqlClient.SqlConnection(cnstr)
cn.Open()
cm = New SqlClient.SqlCommand(cnsql, cn)
dr = cm.ExecuteReader <----Error! it says Invalid column name ' & ProductID & '.

Um.
SQL DELETE operations do not return an SqlReader - only SELECT operations do that - so the system is confused as to what you are trying to do.

Try this instead:

VB

...
cm = New SqlClient.SqlCommand(cnsql, cn)
cm.ExecuteScalar

But the string looks wrong as well, and even if you fix it:

VB

cnsql = "DELETE FROM TbProduct WHERE ProductID= " & ProductID

You are leavign yourself wide open to SQL injection attacks. Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

[edit]"delete TbProduct..." changed to "DELETE FROM TbProduct..." - Oops...[/edit]