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Very New to Programming Need advice .
#1
Hi guys , i trying to develop an app for my son so he can easily admin a mysql database , and after lots of googleing i eventually came across brandons youtube tutorials on sql connection .. Thanks for those man , very helpful.

I have progressed quite well but it seems i have over looked something.

I wanted to make the app useful to others so rather than predetermine the connection string i thought to add simple textbox entries for connection to other DB's of this nature.

Ok so to my problem . to aid in debugging i predetermined the connection string variables to save me typing them in. Now that im ready to try the app i remove the predetermined variable strings and want the textbox entries to come into play.

heres my code :

[code2=vbnet]Imports MySql.Data.MySqlClient

Public Class Form1
'common variables
Public Shared IP As String = "removed for security"
Public Shared DBNAME As String = "removed for security"
Public Shared USER As String = "removed for security"
Public Shared PASS As String = "removed for security"
Public Shared conn_ok As Boolean = False
Public Shared connstr As String = "Server=" & IP & ";Database=" & DBNAME & ";Uid=" & USER & ";Pwd=" & PASS & ";"
Public Shared myConnection As New MySqlConnection(connstr)
Public Shared command As New MySqlCommand
Public Shared adapter As New MySqlDataAdapter
Public Shared data As MySqlDataReader

'connection code
'ip address
Private Sub KryptonTextBox1_TextChanged(sender As System.Object, e As System.EventArgs) Handles KryptonTextBox1.TextChanged
IP = KryptonTextBox1.Text
connstr = "Server=" & IP & ";Database=" & DBNAME & ";Uid=" & USER & ";Pwd=" & PASS & ";"
End Sub
'Database name
Private Sub KryptonTextBox2_TextChanged(sender As System.Object, e As System.EventArgs) Handles KryptonTextBox2.TextChanged
DBNAME = KryptonTextBox2.Text
End Sub
'username
Private Sub KryptonTextBox3_TextChanged(sender As System.Object, e As System.EventArgs) Handles KryptonTextBox3.TextChanged
USER = KryptonTextBox3.Text
End Sub
'password
Private Sub KryptonTextBox4_TextChanged(sender As System.Object, e As System.EventArgs) Handles KryptonTextBox4.TextChanged
PASS = KryptonTextBox4.Text
End Sub
'connection test
Private Sub KryptonButton1_Click(sender As System.Object, e As System.EventArgs) Handles KryptonButton1.Click
' check connection by retrieving sql version
KryptonRichTextBox1.Text = ""
Dim stm As String = "SELECT VERSION()"
Dim Version As String = ""
Try
myConnection.Open()
TextBox1.Text = "Server=" & IP & ";Database=" & DBNAME & ";Uid=" & USER & ";Pwd=" & PASS & ";"
Dim cmd As MySqlCommand = New MySqlCommand(stm, myConnection)
Version = Convert.ToString(cmd.ExecuteScalar())

KryptonRichTextBox1.Text = "Successful connection : connected to PermissionsEx database version : " & Version
conn_ok = True

Catch ex As MySqlException
KryptonRichTextBox1.Text = "Connection Error : Please verify your database info is correct and your internet connection is valid."
conn_ok = False
TextBox1.Text = "Server=" & IP & ";Database=" & DBNAME & ";Uid=" & USER & ";Pwd=" & PASS & ";"
Finally
myConnection.Close()
End Try
' if connection is ok then check db tables exist
If conn_ok = True Then
Try
Dim sqlquery As String = "SELECT * from permissions"
myConnection.Open()
command.CommandText = sqlquery
command.Connection = myConnection
adapter.SelectCommand = command
data = command.ExecuteReader
Catch extable As MySqlException
KryptonRichTextBox1.Text = "Successful connection : connected to mySQL database version : " & Version & ". However no Permissions EX tables are present , please check your database configuration."
Finally
myConnection.Close()
End Try
Else
KryptonRichTextBox1.Text = "Connection Error : Please verify your database info is correct and your internet connection is valid."
End If
End Sub[/code2]

The problem seems to be that if i run my app and hit my connect button without populating the textboxes it connects using my predetermined values no problems.
If i remove my predetermined values and rely on the textboxes connection fails.

I displayed the connection string in a new textbox to see what was going on , when i connect to the db my outputted textbox string is missing the variables , if i fail to connect using the textboxes , the connection string in the debug textbox is fine .

basically what im saying is i cannot seem to push the textbox entries into a successful connection string.

If screenshots of the app would help let me know.


Messages In This Thread
Very New to Programming Need advice . - by pwsincd - 05-02-2013, 11:15 AM

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