CODEWITHSUNDEEP
vb.netms-access
David Sanculane
David Sanculane

Reputation: 3

No value given for one or more required parameters vb.net

Hi all Iam trying to reduce a stock using this code below but Iam getting error, can any one help me pleaseee????`

Public Sub UpdateDecreaseQuantity()
    Try
        Dim cb As String = "Update Dish SET Quantity = stocksOnHand - '" & DataGridView1.CurrentRow.Cells(2).Value & "' "
        con.Open()
        cmd = New OleDbCommand(cb, con)
        cmd.ExecuteNonQuery()

    Catch ex As Exception
        MsgBox(ex.Message)
    Finally
        cmd.Dispose()
        con.Close()
    End Try

End Sub

Upvotes: 0

Views: 60

Answers (2)

Sunil
Sunil

Reputation: 3424

Firstly, If DataGridView1.CurrentRow.Cells(2).Value is 0 length string or Nothing value you will get this error.

Please check using:
Not String.IsNullOrEmpty(DataGridView1.CurrentRow.Cells(2).Value).

Secondly, you have added quotes around the Cell value in the query

'" & DataGridView1.CurrentRow.Cells(2).Value & "' "

Numeric value should not have quotes around.

Thirdly, this query is prone to SQL injection attack. Please try to parameterize the query.

Example:

Dim OtherValue as Integer = 0
Dim cb As String = "Update Dish SET Quantity = stocksOnHand - @OtherValue"
con.Open()
cmd = New OleDbCommand(cb, con)
Int32.TryParse(DataGridView1.CurrentRow.Cells(2).Value, OtherValue)
cmd.Parameters.Add("@OtherValue", SqlDbType.Int).Value = OtherValue
cmd.ExecuteNonQuery()

Upvotes: 1

jmcilhinney
jmcilhinney

Reputation: 54417

Just as you use double quotes to signify a String in VB but do not put them around numbers, so single quotes denote a string in SQL. If you are subtracting two numbers then they must both be numbers, not a one number and a string.

Dim cb As String = "Update Dish SET Quantity = stocksOnHand - " & DataGridView1.CurrentRow.Cells(2).Value.ToString()

Even better would be to learn how to insert values into SQL properly and use parameters.

Upvotes: 0

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