Meet a little problem here which i do not know where the wrong the code
Private Sub SimpleButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SimpleButton1.Click
Dim str As New MemoryStream
Dim Serializetemplate As New DPFP.Template
Serializetemplate.Serialize(str)
Dim serializedTemplate As Byte() = str.ToArray()
'save to database
opencon1()
Dim cmd As MySql.Data.MySqlClient.MySqlCommand
cmd = New MySql.Data.MySqlClient.MySqlCommand
cmd.Parameters.AddWithValue("?imagedata", serializedTemplate)
cmd.Parameters.AddWithValue("?userid", txtEmpid.Text)
cmd.CommandText = "UPDATE master SET fp1=?imagedata WHERE userid=?userid"
cmd.CommandType = CommandType.Text
cmd.Connection = con1
cmd.ExecuteNonQuery()
End Sub
I get an error at Serializetemplate.Serialize(str) with the error message Bad Serialization
Anyone ever meet this error and solve it?
Joseph I'm not very good with VB but as far as I can see you're declaring a new DPFP.Template and then serializing it into your memory stream. Why are you doing this?
Given that you're enrolling or verifying the SDK'll give you the template on the event handler
private void Enrolled(object Control, int Finger, DPFP.Template Template, ref DPFP.Gui.EventHandlerStatus Status)
{
if (Status == DPFP.Gui.EventHandlerStatus.Success)
{
// Here you can use the template as Template.Bytes
}
}
The template is already serialized as byte[].
I think that given that you just create the template (blank) then when you try to serialize it throws the exception.
Related
I hope the title is enough to understand my problem, I already installed whats need to run the ADO.NET, I already have a connection string in my module and data query in my class,
Imports System.Data
Imports System.Data.OleDb
Module GlobalVariables
Public sGlobalConnectionString As String
Friend conString As String
Public dr As OleDbDataReader
Sub Main()
Dim sGlobalConnectionString As New OleDb.OleDbConnection
Dim sDataserver As String
Dim sDatabaseName As String
Dim sDatabaseConnection As String
sDataserver = "localhost"
sDatabaseName = "employee"
sDatabaseConnection = "Driver={MariaDB ODBC 3.1 Driver}; SERVER=" & sDataserver & "; UID=root;PWD=******; Database=" & sDatabaseName & "; PORT=3307; OPTION=3"
sGlobalConnectionString = New OleDb.OleDbConnection(conString)
End Sub
End Module
this is my class
Imports System.Data.OleDb
Public Class clsDataQuery
Public Shared Sub Class_initialize()
Dim con = New OleDb.OleDbConnection
con.ConnectionString = sGlobalConnectionString
con.Open()
End Sub
Public Shared Sub Class_Terminate()
Dim con = New OleDb.OleDbConnection
If Not con Is Nothing Then
con.Close()
con = Nothing
End If
End Sub
Public Function GetRecordDataSet(ByVal sStoreProcName As String, ByVal sParameterList As String)
Dim cmd As New OleDbCommand()
Dim arrParameter, arrParamName
Dim sParamName As String
Dim sDataValue
Dim lCtr As Long
On Error GoTo errhandler
cmd.Connection = New OleDb.OleDbConnection
cmd.CommandTimeout = 1800
cmd.CommandText = CommandType.Text
If Not Trim(sParameterList) = "" Then
arrParameter = Split(sParameterList, "|", , vbTextCompare)
If UBound(arrParameter) >= 0 And IsArray(arrParameter) Then
For lCtr = 0 To UBound(arrParameter)
arrParamName = Split(arrParameter(lCtr), "$", , vbTextCompare)
sParamName = arrParamName(0)
sDataValue = arrParamName(1)
cmd.Parameters.Item(sParamName) = sDataValue
Next lCtr
End If
End If
GetRecordDataSet = cmd.ExecuteReader
cmd = Nothing
Exit Function
errhandler:
MessageBox.Show("Records Not Found!!!")
End Function
End Class
if this button is click, the value of Textbox1.text will search in the database if it is exist, if exist it will continue into another form if not error message will appear, how do i do that?
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim username = txtbox_lastname.Text
If username <> "" Then
Try
clsDataQuery.Class_initialize()
Catch ex As Exception
MessageBox.Show("No Record Found")
End Try
Else
MessageBox.Show("No Record Found!!!")
End If
End Sub
If this is MariaDb then you want to use the provider for MySql. Not ODBC and not OleDb. No wonder you are having problems. There is not much information available for this database compared to the usual Access database used for beginners.
Do not declare database objects anywhere but the method they are used in. You can declare a Private variable for the connection string at the class level.
Although one of these is a Module level variable and one is a local variable, it is very confusing and bad practice. Why would you call a connection object a String?
Public sGlobalConnectionString As String
Dim sGlobalConnectionString As New OleDb.OleDbConnection
BTW, it is fine to declare and initialize your variables in a single line.
Dim sDataserver = "localhost"
You create a new connection on the first line of Sub Main, then you throw it away and create another new connection on the last line. Since sDataServer and sDatabaseName are hard coded why not just put the literal values directly into the connection string.
After all that you pass conStr to the constructor of the connection instead of sDatabaseConnection. Why were you building sDatabaseConnection (another misnomer, it is not a connection, its a string) and then never use it. Has conStr been set elsewhere?
At any rate, throw out the whole module.
Moving on to your DataQuery class. First, the name should begin with an upper case letter.
Get rid of Class_initialize. We don't want to create or open any connection except in the method where it is used. You never call Class_Terminate so dump that too.
The GetRecordDataSet method...
Functions in vb.net require a datatype. The old VB6 syntax of assigning the return value to the name of the function will work but it is not the .net way. In vb.net we use the Return keyword.
You have not initialized or given a datatype to arrParameter, arrParamName or sDataValue which violates Option Strict. (You do have Option Strict On, don't you?)
On Error GoTo errhandler is a sad leftover from VB6. .net languages have structured error handling with Try...Catch...Finally...End Try.
cmd.Connection = New OleDb.OleDbConnection sets the connection property however this new connection has no connection string.
cmd.CommandText = CommandType.Text Now this is just silly. What I think you want is cmd.CommandType =CommandType.StoredProcedure
Using...End Using blocks take care of declaring, closing and disposing database objects even if there is an error. You don't want to return a DataReader because a reader requires an open connection. cmd.ExecuteReader returns a DataReader. I used the reader to load a DataTable and returned the DataTable.
It seems you are trying to develop a factory pattern but it is way too advanced for your. Just pass value and call a method specific to what your are searching for. You want your DataQuery code to be independent from your user interface. The Button code doesn't care where the data is coming from. It could be a database, a text file, or a web service. Likewise the DataQuery code doesn't know where the values are coming from. It could be a WinForms app, a web application or a phone app.
Public Class DataQuery
Private Shared ConStr As String = "server=localhost;userid=root;database=employee"
Public Shared Function SearchByLastName(ByVal LName As String) As DataTable
Dim dt As New DataTable
Using cn As New MySqlConnection(ConStr),
cmd As New MySqlCommand("Select * From PutTableNameHere Where LastName = #LName", cn)
cmd.Parameters.Add("#LName", MySqlDbType.VarChar).Value = LName
cn.Open()
Using reader = cmd.ExecuteReader
dt.Load(reader)
End Using
End Using
Return dt
End Function
End Class
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim dt As DataTable = Nothing
If txtbox_lastname.Text <> "" Then
Try
dt = DataQuery.SearchByLastName(txtbox_lastname.Text)
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End If
DataGridView1.DataSource = dt
End Sub
Before answering, I really think that the GetRecordDataSet() at the very least a darn good tidy up, better yet removed from history
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim username = txtbox_lastname.Text
If username <> "" Then
Try
clsDataQuery.Class_initialize()
Dim reader = GetRecordDataSet("storedProcName", txtbox_lastName.Text)
Do While reader.Read()
'Process record etc
Loop
Catch ex As Exception
MessageBox.Show("No Record Found")
End Try
Else
MessageBox.Show("No Record Found!!!")
End If
End Sub
Might be a bit rough, but should get you heading in the right direction
i implemented a webservice with vb.net
method is like this
Public Class WebService
Inherits System.Web.Services.WebService
<WebMethod()> _
Public Function INSERT_NEW(ByVal i As Integer, ByVal f As String) As String
Dim con As New OleDbConnection
Dim cmd As New OleDbCommand
Try
con.ConnectionString = ConfigurationManager.ConnectionStrings("WebConnectionSTR").ToString
'Dim strMdbPath As String = "C:\Users\Hossein\Documents\Visual Studio 2010\WebSites\WebSite1\"
'Dim strProvider As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="
'Dim strDBFile As String = "db.mdb"
cmd.Connection = con
cmd.CommandText = "insert into tb values (" & i & ",'" & f & "')"
con.Open()
cmd.ExecuteNonQuery()
con.Close()
Return "1"
Catch ex As Exception
con.Close()
Return "0"
End Try
End Function
End Class
it works if i run it and invoke it
but when i create a windows application i occured with an unkown problem
because i used 2 (integer and string) input parameters in web method as input parameters,
INSERT_NEW(byval i as integer,byval f as string) as string
it didnt work
Imports wsdl.Myservice
Public Class Form1
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim s As WebServiceSoap = New WebServiceSoapClient
lblAdd.Text = s.INSERT_NEW(txt1.Text, txt2.Text)
End Sub
End Class
but when i change the input argument in web method to INTEGER it works properly
is it a limitation to use data types in web method in web service OR i did something wrong???
i added these 3 photos to show you the exact error that i get.
You declare your webmethod to receive an Integer and a String. So you should pass an Integer and a String, but your code tries to pass two strings. You should respect the signature of the webmethod and pass the parameters as expected
lblAdd.Text = s.INSERT_NEW(Convert.ToInt32(txt1.Text), txt2.Text)
Of course, here I am assuming that the string in txt1.Text is convertible in an integer.
Said that I wish to point your attention to a very big problem of your code:
What happen if a malicious user pass for the parameter f the following string
"xxxxx');DELETE FROM tb; --"
It is called Sql Injection and could wreak havoc with your database. Try to use ALWAYS a parameterized query when you receieve input from your users and pass it to a database command
Using con = New OleDbConnection(ConfigurationManager.ConnectionStrings("WebConnectionSTR").ConnectionString)
Using cmd = New OleDbCommand("insert into tb values (?, ?)", con)
Try
con.Open()
cmd.Parameters.AddWithValue("#p1",i)
cmd.Parameters.AddWithValue("#p2",f)
cmd.ExecuteNonQuery()
Return "1"
Catch ex As Exception
Return "0"
End Try
End Using
End Using
Finally i found the answer myself
Imports wsdl.Myservice
Imports System.Reflection
Public Class Form1
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim s As WebServiceSoap = New WebServiceSoapClient
Dim method As MethodInfo = s.GetType().GetMethod("INSERT_NEW")
Dim returnValue As Integer = method.Invoke(s, New Object() {CInt(txt1.Text), txt2.Text})
lblAdd.Text = returnValue
End Sub
End Class
I am trying to populate a listbox by retrieving data from a database through sql. I have asked this question earlier but i was using a different configuration and the one i'm using now isn't giving any results.
retrieving data in VB from SQL
That is my old post. I will now provide the code to the newer version of my attempt.
Imports System.Data.Sql
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim conn As New SqlConnection
conn.Open()
Dim comm As New SqlCommand("SELECT name FROM Table_1", conn)
Dim reader As SqlDataReader = comm.ExecuteReader
Dim dt As New DataTable
dt.Load(reader)
ListBox1.Items.Add(dt)
End Sub
End Class
If anyone would be willing to help me out i'd greatly appreciate it. If possible, use a practical approach when trying to enlighten me, as that works best.
edit 1
Imports System.Data.Sql
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim connString As String = "Data Source=THE_SHOGUNATE\SQLEXPRESS;Initial Catalog=le_database;Integrated Security=True"
Dim conn As New SqlConnection(connString)
conn.Open()
Dim comm As New SqlCommand("SELECT name FROM Table_1", conn)
Dim reader As SqlDataReader = comm.ExecuteReader
Dim dt As New DataTable
dt.Load(reader)
ListBox1.DataSource = dt
End Sub
End Class
With this code the listbox populates with 6 instances of "System.Data.DataRowView" strings, 6 being the number of items in my table. How do i get the actual values?
You missed the connectionString
If you want to populate list from DB there are many ways
With DataReader
Imports System.Data.Sql
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim connectionString As String = "Data Sourec=localhost;........."
Dim conn As New SqlConnection(connectionString)
conn.Open()
Dim comm As New SqlCommand("SELECT name FROM Table_1", conn)
Dim reader As SqlDataReader = comm.ExecuteReader
/* As it is not working i commented this
listBox1.ItemsSource = dt; // use this instead of ListBox1.Items.Add(dt)
//because Add event add only one item in the list.
*/
Dim i As Integer
i=0
while reader.read()
listbox1.Items.Add(dr(i).ToString);
i++
End While
End Sub
End Class
With DataTable
Imports System.Data.Sql
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim connectionString As String = "Data Sourec=localhost;........."
Dim conn As New SqlConnection(connectionString)
conn.Open()
// Create new DataAdapter
SqlDataAdapter a = new SqlDataAdapter("SELECT * FROM EmployeeIDs", c)
// Use DataAdapter to fill DataTable
DataTable dt = new DataTable();
a.Fill(dt);
ListBox1.DataSource = dt;
ListBox1.DataTextField = "name";
End Sub
End Class
EDIT:
Other parameters of connection string depends on your security and all that. You must see this link Connection strings for SQL Server 2008
Set the DisplayMember property after DataSource binding:
ListBox1.DataSource = dt
ListBox1.DisplayMember="name"
The last solution I saw should work, but there are a couple important best practices to keep in mind regarding SQL Server.
1) Avoid Select * whenever possible, instead name your columns explicitly. Select * causes SQL to perform extra work if you do not intend to pull down all the columns in the table. It's also not future-proof, since a dba could add a VARBINARY(MAX) column in the future, and populate it with gigs worth of blob data, This scenario would make your query as written slow down substantially and unnecessarily.
2) Always remember to close your SQLConnection when you're done with it. This will free up a SQL connection and resources.
if (cn.State != ConnectionState.Closed)
cn.Close();
Another cool trick is to use the USING directive which will dispose of the SqlConnection object when execution passes out of scope.
using (SqlConnection cn = new SqlConnection(sConnectionString))
{
if (cn.State != ConnectionState.Open)
cn.Open();
// add query code here.
if (cn.State != ConnectionState.Closed)
cn.Close();
}
don't forget to close your SqlDataReader after the read loop is complete.
if (!dr.IsClosed)
dr.Close();
I hope this helps.
Andre Ranieri
I have the following:
Public Interface INorthwindSvc
<OperationContract()>
<WebGet(UriTemplate:="EmployeePictureBytes?id={EmpId}")>
Function GetEmployeePictureBytesById(ByVal EmpId As String) As Byte()
End Interface
I got the method implemented (using EF 4.0) as follows:
Public Function GetEmployeePictureBytesById(ByVal EmpId As String) As Byte() Implements INorthwindSvc.GetEmployeePictureBytesById
Dim ctxt As New NorthwindEntities
Dim q = From c In ctxt.Employees
Where c.EmployeeID = EmpId
Select c.Photo
Return q.FirstOrDefault
End Function
I am able to receive bytes when I access the operation from browser. If I try to access the same using Win Client as follows (an error occurs as shown inline):
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim o As New WebClient
Dim b() As Byte = o.DownloadData(New Uri("http://localhost:8732/WcfWebHttpSvcLib/rest/EmployeePictureBytes?id=2"))
Dim ms As New MemoryStream()
ms.Write(b, 0, b.Length)
Dim original As New System.Drawing.Bitmap(ms) 'error: parameter is not valid
End Sub
I also tried the same using Image.FromStream. But, still no luck.
Can anyone help me on this?
thanks
You're not rewinding the memorystream after writing to it, so trying to read from it will fail That said, even that's unnecessary, as you could just write:
im ms As New MemoryStream(b)
' now call FromStream
I have a bit of code which loads data from a stored procedure in MS SQL Server and then loads the data into a DataGridView, which works fine. What I want is for the code that connects / loads the data to sit in my Database class and then everything associated with the DataGridView to be stored in my Form but I am having problems passing the contents of the BindingSource over to the Form from the Database class.
Form1 code:
Public Class Form1
Dim myDatabaseObj As New Class1()
Dim bindingSource1 As New BindingSource()
Dim connectString As New SqlConnection
Dim objDataAdapter As New SqlDataAdapter
Dim table As New DataTable()
Dim tabletest As New DataTable()
Private Sub loadCompanyList()
Try
Me.dgv_CompanyList.DataSource = Me.bindingSource1
getCompanyList()
Catch ex As NullReferenceException
End Try
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
loadCompanyList()
End Sub
End Class
When I try place the getCompanyList() in a class and then create a new object that references the Form() it does not seem to return any value from the table to the MyForm.BindingSource1.Datasource meaning my DataGridView displays no data.
Database class code:
.....
Private Sub getCompanyList()
Try
Dim myForm as new Form()
connect_Transaction_Database()
objDataAdapter.SelectCommand = New SqlCommand()
objDataAdapter.SelectCommand.Connection = connectString
objDataAdapter.SelectCommand.CommandText = "sp_GetCompanyList"
objDataAdapter.SelectCommand.CommandType = CommandType.StoredProcedure
Dim commandBuilder As New SqlCommandBuilder(Me.objDataAdapter)
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.objDataAdapter.Fill(table)
**MyForm.bindingSource1.DataSource = table**
Catch ex As DataException
MsgBox(ex.Message)
Catch ex As NullReferenceException
MsgBox(ex.Message)
End Try
disconnect_Transaction_Database()
End Sub
This question has just been bumped by the Community user so I thought I would provide an answer which may help others in the future.
Firstly, I would consider implementing Using:
Managed resources are disposed of by the .NET Framework garbage collector (GC) without any extra coding on your part. You do not need a Using block for managed resources. However, you can still use a Using block to force the disposal of a managed resource instead of waiting for the garbage collector.
Secondly, you don't need to use a SqlDataAdapter. Instead you can load a DataTable using the SqlCommand class and return that. I would also contain the SqlConnection in the method rather than having it opened and closed in a different one.
Your code would look something like this:
Form1 code:
Public Class Form1
Private Sub loadCompanyList()
Dim myDatabase As New Database
Me.dgv_CompanyList.DataSource = myDatabase.getCompanyList()
End Sub
End Class
Database code:
Public Class Database
Public Function getCompanyList() As DataTable
Dim dt As New DataTable
Using con As New SqlConnection(connectionString),
cmd As New SqlCommand("sp_GetCompanyList", con) With {.CommandType = CommandType.StoredProcedure}
con.Open()
dt.Load(cmd.ExecuteReader())
End Using
Return dt
End Function
End Class
You want getCompanyList to be a function, which returns a DataTable. Then, forget the BindingSource (if the DataGridView is read-only) and set the DataSource property to the function:
Me.dgv_CompanyList.DataSource = getCompanyList
I would suggest you make the GetCompanyList method into a Function that returns the DataTable filled by the SqlDataAdapter. There's no real reason this Sub should have a dependency on the form. Instead a method in the form could call this to get the DataTable and then perform the binding.
Public Function GetCompanyList() As DataTable
...
...
Dim table As New DataTable()
table.Locale = System.Globalization.CultureInfo.InvariantCulture
Me.objDataAdapter.Fill(table)
Return table
...
...