The given key was not present in the dictionary in vb.net

Question

I'm getting this error in vb.net, when trying to connect to mysql database:

An error occurred creating the form. See Exception.InnerException for details.  The error is: The given key was not present in the dictionary.

I'm reading the database information (user, password, host, database) from a textfile.

 Dim FILE_NAME As String = "D:\connection.txt"

    Dim objReader As New StreamReader(FILE_NAME)


    Public Sub textfileopener()
        host = objReader.ReadLine
        user = objReader.ReadLine
        password = objReader.ReadLine
        database = objReader.ReadLine

        objReader.Close()
    End Sub

Then assigning it to these variables:

Public host 
Public database  
Public user  
Public password

Then finally I connect to the database:

Dim con As New MySqlConnection("Server=" + host + ";Database=" + database + ";Uid=" + user + ";Pwd=" + password + ";")

I think its not getting any values. Because if I assign values right ahead, I can connect without problems:

    Public host = "localhost"
    Public database = "db"
    Public user = "root"
    Public password = "pw

But if I do it this way then it will all be constant. And I cannot change anything at all. My problem is getting the correct values into the connection string. How do I do that?

Update

System.InvalidOperationException was unhandled
  Message="An error occurred creating the form. See Exception.InnerException for details.  The error is: The given key was not present in the dictionary."
  Source="QueryGenerator"
  StackTrace:
       at QueryGenerator.My.MyProject.MyForms.Create__Instance__[T](T Instance) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 190
       at QueryGenerator.My.MyProject.MyForms.get_Form1()
       at QueryGenerator.My.MyApplication.OnCreateMainForm() in C:\Users\Nrew\Documents\Visual Studio 2008\Projects\QueryGenerator\QueryGenerator\My Project\Application.Designer.vb:line 35
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at QueryGenerator.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.Collections.Generic.KeyNotFoundException
       Message="The given key was not present in the dictionary."
       Source="mscorlib"
       StackTrace:
            at System.ThrowHelper.ThrowKeyNotFoundException()
            at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
            at MySql.Data.MySqlClient.MySqlConnectionStringBuilder.get_UserID()
            at MySql.Data.MySqlClient.NativeDriver.Authenticate()
            at MySql.Data.MySqlClient.NativeDriver.Open()
            at MySql.Data.MySqlClient.Driver.Open()
            at MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
            at MySql.Data.MySqlClient.MySqlPool.CreateNewPooledConnection()
            at MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
            at MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
            at MySql.Data.MySqlClient.MySqlPool.GetConnection()
            at MySql.Data.MySqlClient.MySqlConnection.Open()
            at QueryGenerator.connection..ctor() in C:\Users\Nrew\Documents\Visual Studio 2008\Projects\QueryGenerator\QueryGenerator\connection.vb:line 22
            at QueryGenerator.Form1..ctor() in C:\Users\Nrew\Documents\Visual Studio 2008\Projects\QueryGenerator\QueryGenerator\Form1.vb:line 5
       InnerException:

Answer 1

The error is coming from the MySQL client. It appears that it's expecting you to provide a particular parameter in the connection string that you are not. While I'm not familiar enough with the managed MySQL driver to tell you what's missing, the fact that something is missing is pretty clear.

You may want to try adding a space between the semicolon that signals the end of one parameter and the name of the next parameter. Like this:

Dim con As New MySqlConnection("Server=" + host + "; Database=" + database + "; Uid=" + user + "; Pwd=" + password + ";")