Simple: Adding information from a textbox to a string

[chrisdent1986]

Hi there I am creating a system where I link a .net app to a oracle db and am currently working on linking it to the database so that I can add new users for oracle here is my code:

Imports system.Data.OracleClient

Public Class Form1
    Dim OracleConn As New OracleConnection 'Declares the name of the connection
    Dim Command1 As String = "Create user " & txtUsername.text & " default tablespace users defined by password"
    Dim Create As New OracleCommand(Command1, OracleConn)



    Private Sub cmdTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdTest.Click
        Try
            'Attempts to connect to oracle
            OracleConn.ConnectionString = "Data Source=******;User ID=******;Password=******;Unicode=True"
            'Defines connection string
            OracleConn.Open()
            'command for opening connection
            Create.ExecuteNonQuery()
            'Executes the Add Command
            OracleConn.Close()
            'Command for closing connection
            MessageBox.Show("User Added")
            'Displays messagebox if above commands work without problems
        Catch ex As Exception
            'If commands under "try" do not work then message appears
            MsgBox("Error Occurred:" & ex.Message)
        End Try
    End Sub
End Class

I've edited the connection strings and stuff for security reasons as I'm a paranoid android lol.

Anyways the main problem is when declaring the command named "command1" the system runs into some sort of problem

I've tried not having hte text box addition and having hte button click simply create a user (where I filled in the string as create user john..." etc etc and the user was created.

The main problem is something to do with putting the textbox value inbetween the string and I have no idea why it isn't working. I have tried replacing & with + etc but it does not help. The project shows no errors until I run it and then I get a window with:

"An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object."

then a prompt for tooltips online etc. Which dont seem to help at all.

Can someone tell me what I've done wrong have I forgot to put something in or am I going about this the wrong way?

Thanks for your help.

Chris

[chrisdent1986]

Got it working a few minutes after I posted this apologies for wasting peoples time who were searching for a solution.

The problem was I declared the command before the textbox had any value (in the form load section)

so i changed my code like this :

Imports system.Data.OracleClient

Public Class Form1
    Dim OracleConn As New OracleConnection 'Declares the name of the connection
   
    Private Sub cmdTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdTest.Click
        Try
             Dim Command1 As String = "Create user " & txtUsername.text & " default tablespace users defined by password"
    Dim Create As New OracleCommand(Command1, OracleConn)

'Attempts to connect to oracle
            OracleConn.ConnectionString = "Data Source=******;User ID=******;Password=******;Unicode=True"
            'Defines connection string
            OracleConn.Open()
            'command for opening connection
            Create.ExecuteNonQuery()
            'Executes the Add Command
            OracleConn.Close()
            'Command for closing connection
            MessageBox.Show("User Added")
            'Displays messagebox if above commands work without problems
        Catch ex As Exception
            'If commands under "try" do not work then message appears
            MsgBox("Error Occurred:" & ex.Message)
        End Try
    End Sub
End ClassImports system.Data.OracleClient

Public Class Form1
    Dim OracleConn As New OracleConnection 'Declares the name of the connection
    Dim Command1 As String = "Create user " & txtUsername.text & " default tablespace users defined by password"
    Dim Create As New OracleCommand(Command1, OracleConn)



    Private Sub cmdTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdTest.Click
        Try
            'Attempts to connect to oracle
            OracleConn.ConnectionString = "Data Source=******;User ID=******;Password=******;Unicode=True"
            'Defines connection string
            OracleConn.Open()
            'command for opening connection
            Create.ExecuteNonQuery()
            'Executes the Add Command
            OracleConn.Close()
            'Command for closing connection
            MessageBox.Show("User Added")
            'Displays messagebox if above commands work without problems
        Catch ex As Exception
            'If commands under "try" do not work then message appears
            MsgBox("Error Occurred:" & ex.Message)
        End Try
    End Sub
End Class

and now it works fine thanks for the help if anyone was researching for me. Much appreciated.