Expression expected error

Hi,

I have a source code giving "expression expected" error. A small piece of this code below and whole source code is at the attachment. How can I fix this error? Thanks everybody.

-------------------------
Private Sub ConnectToSQL()

Dim con As New SqlConnection
Dim cmd As New SqlCommand
Dim Password As String
Dim Password2 As String
Dim userName As String

Try
If (EXPRESSION EXPECTED)
'change the data source and initial catalog according to your sql server engine and data base
con.ConnectionString = "Data Source = Localhost; Initial Catalog = hdur750; Integrated Security = True"

-----------------------------------------

An If statement needs an expression that evaluates to true or false an If without any condition is meaningless.

Could you post the relevant section of code here please, show the If statement in full if you have to - most people (myself included) would rather not download a word document from an unknown source just to read some source code.

Thank you for your answer. Here is the code. This is a login code in Visual Basic and SQL database

Code:

---

Imports System.Data
Imports System.Data.SqlClient
Public Class giris

    Private Sub giris_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load

    End Sub

    'Login Button
    Private Sub btnlogin_Click(sender As System.Object, e As System.EventArgs) Handles btnLogin.Click

        ConnectToSQL()

    End Sub

    'Connect to SQL method

    Private Sub ConnectToSQL()

        Dim con As New SqlConnection
        Dim cmd As New SqlCommand
        Dim Password As String
        Dim Password2 As String
        Dim userName As String

        Try
            If        (EXPRESSION EXPECTED)
                    'change the data source and initial catalog according to your sql server engine and data base
                con.ConnectionString = "Data Source = Localhost; Initial Catalog = hdur750; Integrated Security = True"
                con.Open()

                cmd.Connection = con
                'change the data fields names and table according to your database
                cmd.CommandText = " SELECT  userid, Password FROM  login WHERE  (userid = '" & txtKullanici.Text & "' ) AND (Password = '" & txtSifre.Text & "')"

                Dim lrd As SqlDataReader = cmd.ExecuteReader()
                If lrd.HasRows Then
                    While lrd.Read()

                        'Do something here
                        Password = lrd("password").ToString()
                        userName = lrd("userid").ToString()

                        Password2 = txtKullanici.Text()

                        If Password = Password2 And userName = txtKullanici.Text Then

                            MessageBox.Show("Logged in successfully as " & userName, "", MessageBoxButtons.OK, MessageBoxIcon.Information
                                        )
                            anasayfa.Show()
                            Me.Hide()

                            'Clear all fields
                            txtKullanici.Text = ""
                            txtSifre.Text = ""

                        End If

                    End While

                Else
                    MessageBox.Show("Username and Password do not match..", "Authentication Failure", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                    'Clear all fields
                    txtSifre.Text = ""
                    txtKullanici.Text = ""
                End If

            End If

        Catch ex As Exception
            MessageBox.Show("Error while connecting to SQL Server." & ex.Message)

        Finally
            con.Close() 'Whether there is error or not. Close the connection.

        End Try

    End Sub

    Private Sub txtKullanici_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtKullanici.TextChanged

    End Sub

    Private Sub txtSifre_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtSifre.TextChanged

    End Sub

    Private Sub btnClear_Click(sender As System.Object, e As System.EventArgs) Handles btnClear.Click
        'User clicking on cancel button only clears field
        ' and refocus to first field

        txtKullanici.Text = ""
        txtSifre.Text = ""
        txtKullanici.Focus()
    End Sub

End Class

---

An If statement is used to make a decision about what code to execute based on checking a condition, if the condition is true then you execute the code, if the condition is false then you would execute the code in the "else" part (if one exists).

You need to decide what you are trying to do here, under what conditions should you be running the code that follows the If statement? Once you have decided on this bit then writing the code to check if it is met should be easy.

If there is no decision to make then you don't need an If statement.

You have a working example of an If further down in the code you posted "If lrd.HasRows Then" and again with "If Password = Password2 And userName = txtKullanici.Text Then"

I copied this code from Internet and changed the name of TextBox, Label, Button, Database ..etc. according to my Project.
In original source code there is not any expression after "If" where the mistake happens. So I couldn't find any solution here.


Thanks for your interest a lot.

If there is nothing needed then just delete the If and the matching End If and you should be fine.

As you don't know what it would be used for, it would be best to remove that "If" line, and the matching "End If" (just before the Catch).


edit: I was too slow!

Hi...
Well the first use of a IF in there i can think of is to check if the Textbox's controls are empty or not, so here is a sample code:

Code:

---

Private Sub ConnectToSQL()

        Dim con As New SqlConnection
        Dim cmd As New SqlCommand
        Dim Password As String
        Dim Password2 As String
        Dim userName As String

        Try
            If txtKullanici.Text <> "" And txtSifre.text <> "" Then

                'change the data source and initial catalog according to your sql server engine and data base
                con.ConnectionString = "Data Source = Localhost; Initial Catalog = hdur750; Integrated Security = True"
                con.Open()

                cmd.Connection = con
                'change the data fields names and table according to your database
                cmd.CommandText = " SELECT  userid, Password FROM  login WHERE  (userid = '" & txtKullanici.Text & "' ) AND (Password = '" & txtSifre.Text & "')"

                Dim lrd As SqlDataReader = cmd.ExecuteReader()
                If lrd.HasRows Then
                    While lrd.Read()

                        'Do something here
                        Password = lrd("password").ToString()
                        userName = lrd("userid").ToString()

                        Password2 = txtKullanici.Text()

                        If Password = Password2 And userName = txtKullanici.Text Then

                            MessageBox.Show("Logged in successfully as " & userName, "", MessageBoxButtons.OK, MessageBoxIcon.Information
                                        )
                            anasayfa.Show()
                            Me.Hide()

                            'Clear all fields
                            txtKullanici.Text = ""
                            txtSifre.Text = ""

                        End If

                    End While

                Else
                    MessageBox.Show("Username and Password do not match..", "Authentication Failure", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                    'Clear all fields
                    txtSifre.Text = ""
                    txtKullanici.Text = ""
                End If

            End If

        Catch ex As Exception
            MessageBox.Show("Error while connecting to SQL Server." & ex.Message)

        Finally
            con.Close() 'Whether there is error or not. Close the connection.

        End Try

    End Sub

---

But as refered in the upper coments, if you using a "IF" clause its to validate a condition TRUE, FALSE, EQUAL, Superior, Inferior, Diferent, etc.... so when you looking for help especify what do you want to do.

https://docs.microsoft.com/en-us/dot...else-statement


PS: You can also be wanting to check if the database exists, if SQL server is there, explain what you want to do maybe people will be able to help.