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validate if value is in database

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User1717218719 posted

Hi All

I have a textbox ehich gets results from the database base on the value entered into the textbox. I am looking to do a validation check. eg. if value entered in textbox is in sql database then write "Error: Invalid Value". I am not sure how to go about this in Vb

any help would be great

Thanks

Monday, August 19, 2019 8:17 AM

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User288213138 posted

Hi E.RU,

According to your description, I made a demo for your reference.

You can use Ado.net to query the values in the database, and then compare the values of the textbox with the data that you query.

The code:

<div>
            Check from database:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br />
            <asp:Button ID="Button1" runat="server" Text="Check" OnClick="Button1_Click" /><br />
            <asp:Label ID="Label1" runat="server"></asp:Label>
        </div>

Private flage As Boolean = False

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString

        Using con As SqlConnection = New SqlConnection(constr)

            Using cmd As SqlCommand = New SqlCommand("SELECT CustomerId FROM Customer where Name='n1'")
                cmd.Connection = con
                con.Open()
                Dim sdr As SqlDataReader = cmd.ExecuteReader()

                While sdr.Read()

                    If sdr(0).ToString() = TextBox1.Text Then
                        flage = True
                        Exit While
                    End If
                End While

                If flage = True Then
                    Label1.Text = "Invalid Value"
                Else
                    Label1.Text = "valid Value"
                End If
            End Using
        End Using
End Sub

The result:

Best regards,

Sam

Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM

Tuesday, August 20, 2019 2:18 AM

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validate if value is in database

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