Question

I keep getting error on my WinForms application whenever I create new database and insert data.

This is how I create the database

Public Function CreateDatabase() As String
    Dim ds As String = "Data Source=" + (My.Computer.FileSystem.SpecialDirectories.MyDocuments) + "\" + (Application.ProductName) + "\" + (DBName) + ".wv" + ";Persist Security Info=True;"
    Dim Conn As New SqlCeConnection(ds)
    Dim Cmd1 As New SqlCeCommand()
    Dim Cmd2 As New SqlCeCommand()
    Dim SqlCeDB As New SqlCeEngine(ds)
    Dim Msg As String
    Try
        If Not System.IO.File.Exists(DBName) Then
            Msg = "Database successfully created in " & Application.StartupPath
            SqlCeDB.CreateDatabase()
            Cmd1.Connection = Conn
            Conn.Open()
            'Create acPassword Table
            Cmd1.CommandText = "CREATE TABLE [wvAccount](" & _
                                "[acName] [nvarchar](100) NOT NULL, " & _
                                "[acPassword] [nvarchar](100) NOT NULL," & _
                                "[acKeyFile] [nvarchar](64) NULL, " & _
                                "[acLastLogin] [nvarchar](100) NULL, " & _
                                "[acLastModified] [nvarchar](100) NULL)"
            Cmd1.ExecuteNonQuery()
            'Create pmPassword Table
            Cmd2.Connection = Conn
            Cmd2.CommandText = "CREATE TABLE [wvPassword](" & _
                                "[pmID] [int] CONSTRAINT pmID PRIMARY KEY NOT NULL, " & _
                                "[pmCat] [nvarchar](100) NOT NULL, " & _
                                "[pmTitle] [nvarchar](100) NOT NULL," & _
                                "[pmUsername] [nvarchar](100) NOT NULL," & _
                                "[pmSiteURL] [nvarchar](100) NULL," & _
                                "[pmNotes] [nvarchar](300) NULL)"
            Cmd2.ExecuteNonQuery()
        Else
            Msg = "There is already a Database with that name."
        End If
    Catch ex As Exception
        Msg = ex.Message
    End Try
    Return Msg
End Function

And this is how I insert the data right after I create the database and populate with table

Private Sub ADD_PA()
    Dim StrSQL_vault As String = "INSERT INTO [wvAccount] ([acName], [acPassword], [acKeyFile], [acLastLogin], [acLastModified]) VALUES (@acName, @acPassword, @acKeyFile, @acLastLogin, @acLastModified)"
    classlibrary_vault = New ConnectionLibrary_Vault
    classlibrary_vault.openConnection_vault(strconnection_vault)
    If Not classlibrary_vault.isConnectionOpen_vault() Then
        Exit Sub
    End If
    classlibrary_vault.initializeCommand_vault(StrSQL_vault)
    classlibrary_vault.addParameter_vault("@acName", SqlDbType.NVarChar, txtName.TextLength, txtName.Text)
    classlibrary_vault.addParameter_vault("@acPassword", SqlDbType.NVarChar, txtEncryptedCode.TextLength, txtEncryptedCode.Text)
    classlibrary_vault.addParameter_vault("@acKeyFile", SqlDbType.NVarChar, txtKeyFile.TextLength, txtKeyFile.Text)
    classlibrary_vault.addParameter_vault("@acLastLogin", SqlDbType.NVarChar, txtLastLogin.TextLength, txtLastLogin.Text)
    classlibrary_vault.addParameter_vault("@acLastModified", SqlDbType.NVarChar, txtLastModified.TextLength, txtLastModified.Text)
    Try
        objcommand_vault.ExecuteNonQuery()
        txtAccountName.Text = txtName.Text
        'Set controls
        _Main.NotifyIcon.Visible = True
        _Main.NotifyIcon.ShowBalloonTip(1, Application.ProductName, VAULT_CREATED, ToolTipIcon.Info)
        Me.ParentForm.Controls.Remove(Me)
        controlManagePasswords()
    Catch ex As Exception
        DevComponents.DotNetBar.MessageBoxEx.Show(ex.Message, Application.ProductName, MessageBoxButtons.OK, MessageBoxIcon.Information)
    End Try
End Sub

At first when I had a primary key on my wvAccount table, I experienced no problem but now I keep getting

Database cannot be null, the empty string, or string of only
whitespace.

I have no problem creating the database, the only thing bothers me is when I try to insert a data on wvAccount. Btw, I’m using SQL Server CE 4.0 and VB.Net

The .wv extension allows me to read and write on my database previously, so probably, there’s no problem with that.

Answer 1

Solved it myself. I forgot to initiate the same connection string I used to create the database, instead I used the connection string for different database. Dumb me. I really have to sleep now.

Dim ds As String = "Data Source=" + (My.Computer.FileSystem.SpecialDirectories.MyDocuments) + "\" + (Application.ProductName) + "\" + (DBName) + ".wv" + ";Persist Security Info=True;"