What I am trying to do is do the basic insert, refresh and update mysql querys in my vb.net application. The refresh, and the insert work perfect the only one I can't get is the update can anyone tell me what I am doing wrong? Here is a picture of the program layout:
http://i.imgur.com/mHxKGrb.png
and here is my source code:
Private Sub KnightButton3_Click(sender As Object, e As EventArgs) Handles KnightButton3.Click
cn = New MySqlConnection
cn.ConnectionString = "my info"
Try
cn.Open()
Dim query As String
Dim command As MySqlCommand
query = "UPDATE Refers.exploitsociety SET Refferals='" + refupdate.Text + "' WHERE Refferals='" + DataGridView1.CurrentCell.Selected + "';"
command = New MySqlCommand(query, cn)
cmd.ExecuteNonQuery()
Catch ex As MySqlException
MessageBox.Show(ex.Message)
Finally
cn.Dispose()
End Try
cn.Close()
End Sub
I think your problem is in the usage of the property Selected of the CurrentCell. This is a boolean value and it is not the content of that cell.
I would use this kind of code with a parameterized query and a using statement around disposable objects
Try
query = "UPDATE Refers.exploitsociety " & _
"SET Refferals=#refs " & _
"WHERE Refferals=#oldrefs"
Using cn = New MySqlConnection(".... connection string ....")
Using command = New MySqlCommand(query, cn)
cn.Open()
command.Parameters.Add("#refs", MySqlDbType.Int32).Value = _
Convert.ToInt32(refupdate.Text)
command.Parameters.Add("#oldrefs", MySqlDbType.Int32).Value = _
Convert.ToInt32(DataGridView1.CurrentCell.Value.ToString())
command.ExecuteNonQuery()
End Using
End Using
Catch ex As MySqlException
MessageBox.Show(ex.Message)
End Try
Notice that with a using statement you don't need to close/dispose the connection because this is automatically done when the code leaves the using block (also in case of exceptions)
Related
I have found a few articles that are similar to my question, and I have tried the suggestions in those articles and none of them have worked for me. What I need seems to be fairly simple and straight forward. (I am able to complete this same action with SQL Server, just not with MySQL. This 'description' information must come a MySQL db)
I have a Listbox and as the user clicks on listbox items, I would like a 'description' label to update with a value pulled from a MySQL database.
I created a public sub in the Module, and I'm calling the sub from the Listbox1_SelectedIndexChanged event (also tried Listbox1_mouseclick event).
However, everything I have tried does not update the label. Any suggestions would be greatly appreciated.
here is the code being used to pull and attempt to populate the label:
Dim conn As New MySqlConnection(My.Resources.MySqlstr)
Try
conn.Open()
Dim cmd As MySqlCommand = New MySqlCommand("select Description from resourceaccess where tid = '" & ReportPicker.ListBox1.ValueMember & "' ", conn)
Dim reader As MySqlDataReader = cmd.ExecuteReader()
While reader.Read()
ReportPicker.Label3.Text = reader.GetString("Description")
End While
reader.Close()
Catch ex As MySqlException
MessageBox.Show(ex.Message)
Finally
conn.Close()
End Try
I don't know if something else is wrong too but this definitely is:
Dim cmd As MySqlCommand = New MySqlCommand("select Description from resourceaccess where tid = '" & ReportPicker.ListBox1.ValueMember & "' ", conn)
Apart from the fact that you should be using a parameter there, the use of ValueMember can't possibly be right. That's the name of a column, not a value from that column. You should be using SelectedValue, which is the value from that column for the item that's selected.
here is what worked:
Dim cs As String = My.Resources.MySqlstr
Dim stm As String = "select Description from resourceaccess where resource = '" & ReportPicker.ListBox1.Text & "' "
Dim conn As MySqlConnection = New MySqlConnection(cs)
Try
conn.Open()
Dim cmd As MySqlCommand = New MySqlCommand(stm, conn)
ReportPicker.Label3.Text = Convert.ToString(cmd.ExecuteScalar())
Catch ex As MySqlException
MessageBox.Show(ex.Message)
Finally
conn.Close()
End Try
I am trying to make a little program that writes and reads from a Mysql database. The reading part is going well, but I am a bit stuck in the write part.
This is my code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Absenden.Click
Dim conn As New MySqlConnection
Dim command As MySqlCommand
Dim myConnectionString As String
myConnectionString = "server=Nothing;uid=to;pwd=see;database=here;"
conn.ConnectionString = myConnectionString
Try
conn.Open()
Dim Querywrite As String
Querywrite = "select * FROM here.message INSERT INTO message admin='" & TB_Name.Text & "' and message='" & TB_Nachricht.Text & "' and Server='" & TB_Server.Text & "' and status='" & TB_Status.Text & "' "
command = New MySqlCommand(Querywrite, connection)
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
conn.Close()
End Sub
The Querywrite part is the problem I think. The input comes from Textboxes in a Windows Form.
Thanks for your help!
Perhaps, if someone shows you once then you will get the idea. The main thing is to always use parameters; not only will you avoid minor sytax and type errors but you will avoid major disasters of malicious input. I guessed at the datatypes of your fields. Please check your database for the types and adjust your code accordingly.
Private Sub InsertData()
Dim strQuery As String = "Insert Into message (admin, message, Server, status) Values (#admin, #message, #Server, #status);"
Using cn As New MySqlConnection("your connection string")
Using cmd As New MySqlCommand With {
.Connection = cn,
.CommandType = CommandType.Text,
.CommandText = strQuery}
cmd.Parameters.Add("#admin", MySqlDbType.VarString).Value = TB_Name.Text
cmd.Parameters.Add("#message", MySqlDbType.VarString).Value = TB_Nachricht.Text
cmd.Parameters.Add("#Server", MySqlDbType.VarString).Value = TB_Server.Text
cmd.Parameters.Add("#status", MySqlDbType.VarString).Value = TB_Status.Text
cn.Open()
cmd.ExecuteNonQuery()
cn.Close()
End Using
End Using
End Sub
It doesn't show me any error and tells me its saved. If I replace the userlable.text with a real value in the database, it works. But with the userlable.text its not working. I have done something similar on another vb.form and it worked so why wouldn't this? It doesn't update in T1Marks on the row where the username is but it says it worked. Any help please?
Private Sub Finish1Button_Click(sender As Object, e As EventArgs) Handles Finish1Button.Click
con = New MySqlConnection
con.ConnectionString = "server=localhost;userid=root;password=Red-grape01;database=math"
Try
con.Open()
Dim Order As String
Order = "update math.marks set T1Marks='" & MarkLable.Text & "' WHERE Username='" & userlabel.Text & "'"
cmd = New MySqlCommand(Order, con)
datareader = cmd.ExecuteReader
MessageBox.Show("Saved")
con.Close()
Catch ex As MySqlException
MessageBox.Show("Error")
Finally
con.Dispose()
End Try
ExamTopicSelectionPage.Show()
Me.Close()
End Sub
Just last friday this code was working perfectly and I was able to create a table in MySQL database but now its showing an error "Timeout in IO operation", need solution guys thanks.
Private Sub toCreateTable()
Dim varString As String = "tablenaming"
Dim Query As String
Dim con As MySqlConnection = New MySqlConnection("server=192.168.0.1; user=logging; database=db_logging; port=3306; password=passing;")
con.Open()
Query = "CREATE TABLE `" & varString & "` ( usernames varchar(50) ) "
Dim cmd As New MySqlCommand(Query, con)
If (cmd.ExecuteNonQuery()) Then
End If
con.Close()
End Sub
Try catch.... Put this in place of your If Then End If.
Try
cmd.ExecuteNonQuery()
'any other code that needs to be completed after running query
Catch ex As Exception
MsgBox(ex.Message)
Finally
con.Close()
End Try
Then let us know if you get any exception message
i want to update mysql table from unbound datagridview rows, i'm using an unbound datagridview because when i want to add the bound datagridview with odbc driver my VS2005 not responding.
Using connection As New MySqlConnection(connectionString)
Dim cmdText As String = "UPDATE titem set no = '" & TextBoxX1.Text & "', kdbarang = #column1 "
Dim command As New MySqlCommand(cmdText, connection)
connection.Open()
Dim transaction As MySqlTransaction = connection.BeginTransaction()
command.Transaction = transaction
Try
For i As Integer = 0 To dgvitem.Rows.Count - 2
command.Parameters.Clear()
command.CommandText = cmdText
command.Parameters.Add("#Column1", MySqlDbType.VarChar).Value = dgvitem.Rows(i).Cells(1).Value
command.ExecuteNonQuery()
Next
MessageBox.Show("Data Berhasil Disimpan")
Catch ex As Exception
MessageBox.Show(ex.Message)
Finally
connection.Close()
End Try
End Using
End Sub
no error, but the result not correct. The looping update its fail and i dont know how.
please some one give me reference to solve it. Thank you.