I'm trying to get the Json value and put it in a label, the syntax seems to be correct, but there sure is something wrong with the code, the value simply doesn't display on the Label. What can it be?
NOTE: I have already added the Newstonsoft JSON reference and the timer is 5 seconds and is activated after the form is loaded.
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Dim json = New IO.StreamReader(DirectCast(DirectCast(Net.WebRequest.Create("https://www.bitstamp.net/api/ticker/"), Net.HttpWebRequest).GetResponse, Net.HttpWebResponse).GetResponseStream)
Dim rq As Newtonsoft.Json.Linq.JToken = Newtonsoft.Json.Linq.JObject.Parse(json.ReadToEnd)
BitCoinPrice = $"{rq.SelectToken("last")}"
Label1.Text = BitCoinPrice
End Sub
I was inattentive but realized that I put the code to activate the Timer1 in the wrong place, instead of putting it when the form loads, it was in when WebBrowser1 loads.
Wrong
Private Sub WebBrowser1_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
Timer1.Enabled = True 'Wrong Place
End Sub
Correct
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Timer1.Enabled = True 'Correct Place
End Sub
Sorry for the inconvenience and thanks for the help.
Related
I need to open a web page which takes some time to load and then read data from the HTML. I used this :
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ie = CreateObject("InternetExplorer.Application")
ie.Visible = True
ie.Navigate("Web page which takes some time to load")
Timer1.Interval = 5000 '5s
Timer1.Start()
End Sub
As I was not able to read easily the HTML, I found some code on the web and I added this to convert to HtmlAgilityPack
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Dim Doc As New HtmlAgilityPack.HtmlDocument
Doc.LoadHtml(ie.document)
End Sub
But unfortunately, I get the error : the conversion from HTMLDocumentClass to String is not possible.
I tried to use "ieDoc As HtmlDocument" instead of "ie As Object" but with no succes. I tried a lot of examples that I found on the web but I was not able to fix this.
Can someone help me ?
Here's the link for the error
Public Class frmMenu
Private Sub UserMaintenanceToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles UserMaintenanceToolStripMenuItem.Click
frmUser.Show()
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
Me.StatusStrip1.Items(0).Text = strUser
Me.StatusStrip1.Items(1).Text = Today()
Me.StatusStrip1.Items(2).Text = TimeOfDay()
End Sub
End Class
After I log in an existing user the error appears.
The Items array of the StatusStrip1 element has no items. You need to make sure to fill it before you try to acces it.
I have issue with passing data in VB.NET and I'm new in vb.net + mysql. I don't know is it possible or not. I have some TextBoxes and I want fill those with userID or something. I want to make this like a modal on php.
When I clik TextBox, 1 form shows up with ComboBox and submit button to pass data to TextBox on previous Form. I've done it with 1 TextBox, but I can't pass it to other TextBox. Here is my code:
Form1.vb
Private Sub TextBox4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox4.Click
'This is method **in my logic** can throw back data to TextBox4 from Form2.vb'
Form2.Label1.Text = TextBox4.Name
Form2.Show()
End Sub
Form2.vb
Private Sub AddTeam_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Call getUSers()
End Sub
Sub getUSers()
Call connection()
Dim str As String
str = "SELECT id FROM users WHERE status='Active'"
cmd = New MySqlCommand(str, conn)
rd = cmd.ExecuteReader
If rd.HasRows Then
Do While rd.Read
ComboBox1.Items.Add(rd("id"))
Loop
Else
End If
ComboBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend
ComboBox1.AutoCompleteSource = AutoCompleteSource.ListItems
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim nik = ComboBox1.SelectedItem
'Here is the issue, if i pass to 1 TextBox (like TextBox4 as sample) it`s easy, but if pass to another TextBox i have no idea to do that'
Form1.TextBox4.Text = nik
Me.Refresh()
Me.Close()
End Sub
note: I know there are many ways to do so, like change TextBox to ComboBox and fill with data, but I want this method
I'm sorry for my poor logic in vb.net. I was better with PHP before.
I am writing a program which lets users upload a large file, compare it to another large file uploaded before and return a list of new entries and discontinued entries.
This requires the program to run a few queries, so it takes a while for the program to complete the task.
Of course, this means that until the program is done with the task, the user cannot do anything else. To prevent that from happening I have included a BackgroundWorker to the project.
The problem is, the BackgroundWorker doesn't start, giving me the same problem.
Can you please help me with this problem? Thanks!
Code:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim opendialog As New OpenFileDialog
Dim filepath As String = ""
Dim cellvalue(20) As String
opendialog.Title = "Elija el archivo que quiere importar"
opendialog.Filter = "CSV (*.csv)|*.csv"
If opendialog.ShowDialog() = DialogResult.Cancel Then
Exit Sub
End If
filepath = Replace(opendialog.FileName, "\", "\\")
Label1.Visible = True 'This is supposed to appear first, but it doesn't appear until the end of the method.
'Reading CSV file content
Cmd.CommandText = "SELECT COUNT(*) AS cuenta FROM libros WHERE 1"
rs = Cmd.Execute
If rs("cuenta").Value = 0 Then
BackgroundWorker1.RunWorkerAsync()
'MySQL queries, some of which takes a long time due to the large file being processed
Beep()
MsgBox("Archivo exportado con éxito",, "Exito")
BackgroundWorker1.CancelAsync()
Else
BackgroundWorker1.RunWorkerAsync()
'MySQL queries, some of which takes a long time due to the large file being processed
Beep()
MsgBox("Archivo exportado con éxito",, "Exito")
BackgroundWorker1.CancelAsync()
End If
End Sub
Private Sub BackgroundWoker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
' Update the progress bar
Me.ProgressBar1.Value = e.ProgressPercentage
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
If e.Cancelled Then
Label1.Text = "Cancelled"
Else
Label2.Text = "Completed"
End If
End Sub
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object,
ByVal e As System.ComponentModel.DoWorkEventArgs) _
Handles BackgroundWorker1.DoWork
' Do some time-consuming work on this thread.
System.Threading.Thread.Sleep(5)
End Sub
RunWorkerAsync is, as the name implies, an async method call. This means that the only work done here is to start the DoWork event handler and return immediately. Thus your code now has two paths of execution, the one in the DoWork event handler (that has just started its work and it has probably done nothing) and the code that follows the call to RunWorkerAsync (the code in the ButtonClick).
This last code shows a messagebox and then call CancelAsync, and you could imagine what this call do to your DoWork thread of execution.
So you just need to wait before displaying anything and the Completed event is exactly what you need to use to wait the completition of your DoWork event handler
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
.....
BackgroundWorker1.RunWorkerAsync()
' Remove these lines....
' Beep()
' MsgBox("Archivo exportado con éxito",, "Exito")
' BackgroundWorker1.CancelAsync()
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
If e.Cancelled Then
Label1.Text = "Cancelled"
Else
Label2.Text = "Completed"
' Add the message here....'
Beep()
MsgBox("Archivo exportado con éxito",, "Exito")
' Of course at this point you don't need to cancel anything....'
End If
End Sub
Private Sub BackgroundWoker1_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
Me.ProgressBar1.Value = e.ProgressPercentage
End Sub
Private Sub BackgroundWorker1_DoWork(ByVal sender As System.Object,
ByVal e As System.ComponentModel.DoWorkEventArgs) _
Handles BackgroundWorker1.DoWork
' Now suppose that your work here could be divided in 5 methods'
ExecuteMethod1()
backgroundWorker1.ReportProgress(20)
ExecuteMethod2)
backgroundWorker1.ReportProgress(40
ExecuteMethod3
backgroundWorker1.ReportProgress(60)
ExecuteMethod4
backgroundWorker1.ReportProgress(80)
ExecuteMethod5
backgroundWorker1.ReportProgress(100)
End Sub
I'm trying to get the InnerHtml of a child of a child of an element. Here is what I have:
If doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble") IsNot Nothing Then
Dim el As HtmlElement = doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble")
inboxTxt.Text = el.Children(1).Children(0).InnerHtml.ToString
End If
And this is the error I'm receiving:
"Object reference not set to an instance of an object."
How do I fix this?
Edit: When I removed the "Try" function, the error was shown here:
If doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble") IsNot Nothing Then
You are making the assumption that your doc object has a value. Try checking if it is nothing also, before you check for child elements.
If Not IsNothing(doc) Then
If Not IsNothing(doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble")) Then
Dim el As HtmlElement = doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble")
inboxTxt.Text = el.Children(1).Children(0).InnerHtml.ToString
End If
End If
Updated Code. This Works but does not return your HtmlElement
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
wb.Navigate("http://www.roblox.com/user.aspx?id=3659905")
End Sub
Private Sub Form1_MouseClick(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseClick
Dim doc As HtmlDocument = wb.Document
If Not IsNothing(doc) Then
Dim el As HtmlElement = doc.GetElementById("ctl00_cphBanner_MenuRedesign_BannerAlertsAndOptionsLoginView_BannerAlertsAndOptions_Authenticated_FriendsBubble")
If el IsNot Nothing Then
inboxTxt.Text = el.Children(1).Children(0).InnerHtml.ToString
Else
inboxTxt.Text = "No Data"
End If
End If
End Sub
End Class
Most likely, at least one of the expressions el.Children(1), el.Children(1).Children(0), or el.Children(1).Children(0).InnerHtml results in null/Nothing. Check each of those, in order, to make sure you actually have a value.