Visual Basic

Problem with catching exceptions

21-Mar-09 21:28

Are the computers on the same networks?

Ignore your application for a moment, can you ping the target from the command prompt? If you cannot do that from windows, then your app won't see the target.

Dave
Who am I?: http://www.bebo.com/daveauld/

Badmafia21-Mar-09 14:57

Badmafia

21-Mar-09 14:57

I'm trying to validate that all boxes are filled in by the user and not left blank.

'check for missing data
        Try
        Catch TitleException As Exception
            If txtbxMovieTitle.Text = "" Then
                MessageBox.Show("Please enter a movie title.", "Data Entry Error", _
                        MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            End If
            With txtbxMovieTitle
                .Focus()
                .SelectAll()
            End With
        End Try
        Try
        Catch DataException As Exception
            If radbtnDVD.Checked = False Or radbtnVHS.Checked = False Then
                MessageBox.Show("Please select a movie type.", "Enter movie type", _
                                 MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            End If
        End Try

Re: Problem with catching exceptions

nlarson1121-Mar-09 15:45

nlarson11

21-Mar-09 15:45

i think your a little confused. Within your try is where you put your logic that could cause the app to "blow up" the catch is where you want to control what happens if the blow up occurs.

Ex:

try
    'do you test here
catch ex as exception
    'tell the user what happened by showing the exception
    msgbox(ex.tostring)
    exit sub
end try

'Never argue with an idiot; they'll drag you down to their level and beat you with experience.' ~ anonymous

'Life's real failure is when you do not realize how close you were to success when you gave up.' ~ anonymous

Re: Problem with catching exceptions

George B Gilbert21-Mar-09 16:45

George B Gilbert

21-Mar-09 16:45

I've found that the simplest method for testing whether a textbox has been populated by the user is to test the length of the text.

If Textbox1.Text.Length <= 0 then
    Msgbox("An entry is required in Textbox1")
    Textbox1.Focus
    Exit Sub
End If

If spaces are also an invalid entry, a simple addition handles that case as well.

If Textbox1.Text.Trim.Length <= 0 then
    Msgbox("An entry is required in Textbox1")
    Textbox1.Focus
    Exit Sub
End If

How could you select an item in listview from a different tabpage?

JUNEYT21-Mar-09 13:48

JUNEYT

21-Mar-09 13:48

Hi,

I have a tabcontrol with 2 tab pages. First tab page has a populated listview control and 2nd tabpage I have a button. My aim is to select the 3rd item in the listview when I clik a button in 2nd tabpage. However I also want to highlight the selected item in listview. Therefore when I go back to 1st tab page from 2nd, the listview should got focused and the 3rd item should be higlighted. How could you do that?

When I primitavely select the item in listview (in code) while I am in 2nd tabpage, the item is not getting selected and no highlight of course.

Thanks.

What a curious mind needs to discover knowledge is noting else than a pin-hole.

Re: How could you select an item in listview from a different tabpage?

George B Gilbert21-Mar-09 17:41

George B Gilbert

21-Mar-09 17:41

There should be no problem with selecting an item in a listview from another tab. What may be happening is that when the 1st tab is selected, another control on the tab (or the tab itself) is receiving the focus. If that's true and the listview HideSelection property is True, the selected item would not be highlighted until the listview receives the focus.

You might check the tab sequence for all of the controls in the form to ensure the focus is going where you want it when each tab is selected. If that doesn't work, in the 1st tab's GotFocus event you could set the focus to the listview control.

Re: How could you select an item in listview from a different tabpage?

JUNEYT22-Mar-09 0:51

JUNEYT

22-Mar-09 0:51

Thanks for responding to my post.

It is still not working even I set the focus for the listview in tabcontrols tabpage. The following statement is not setting the selected item somehow. When I set the item and then when I go back to first tab where the listview is, the listview still doesn't receive the focuse even I set the (listview1.focus()) in tabpage Got_Focuse event procedure. IF listview had received teh focuse, the selected item should be highlighted automatically.

Private Sub ToolStripComboBox2_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ToolStripComboBox2.SelectedIndexChanged
    Dim ICount As Int32 = 0

    '**
    ListView1.SelectedItems.Clear()

    Me.Cursor = Cursors.WaitCursor

    For Each LItem As ListViewItem In ListView1.Items

        If LItem.SubItems(7).Text = ToolStripComboBox2.SelectedItem.ToString _
           Or InStr(LItem.SubItems(7).Text, ToolStripComboBox2.SelectedItem.ToString) > 0 Then


            'HERE IS HOW I SET THE X ITEM AS SELECTED IN LISTVIEW

            ListView1.Items(ICount).Selected = True

            'Here if user selects a song in the list it will be played while Media tab is focused
            '
            If TabControl2.SelectedTab Is TabPage7 Then '**
                Call PlayMusic()
            End If

            Me.Cursor = Cursors.Default
            Exit Sub
        End If
        ICount += 1
    Next

    Me.Cursor = Cursors.Default
End Sub

Private Sub TabPage5_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TabPage5.GotFocus
    Call PopulateSearchBox(ListView1, 7)
    ListView1.Focus()  'HERE I SET THE FOCUSE FOR THE LISTVIEW
End Sub

What a curious mind needs to discover knowledge is noting else than a pin-hole.

Re: How could you select an item in listview from a different tabpage?

George B Gilbert22-Mar-09 5:22

George B Gilbert

22-Mar-09 5:22

Two items come to mind while reviewing the code.

1. The Listview1.SelectedItems.Clear statement in the ToolStripComboBox2_SelectedIndexChanged Sub appears to be unnecessary. If the listview MultiSelect property is set to False as it should be, the user's previous selection will remain selected until a new selection is made and the "ListView1.Items(ICount).Selected = True" statement is executed.

2. What is happening in the PopulateSearchBox procedure that is called in the TabPage5.GotFocus event? Is there something going on in that procedure that is affecting the listview item selection? Since the listview control is one of the parameters for that procedure, it looks suspect.

I think that exhausts my ideas on this issue. The only other suggestion I have is to set an appropriate Breakpoint and walk through the code to hopefully find where the listview selection is being lost.

Writing an Excel table to a DataTable / The values from Excel-cells with "date"-format are not assumed

TheSolid21-Mar-09 3:19

TheSolid

21-Mar-09 3:19

Hi,

I want to read a cell-value from an Excel-worksheet in VB.NET 2005 with the following function:

Private Function strCellValue(ByVal strFilname As String, ByVal strWorksheet As String, ByVal strCell As String) As String

  Dim dtDataTable As New DataTable
  Dim dbConnection As OleDb.OleDbConnection
  Dim dbDataAdapter As OleDb.OleDbDataAdapter
  dbConnection = New OleDb.OleDbConnection
  dbConnection.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; " & "Data Source=" & strFilename & ";" & "Extended Properties='Excel 8.0;HDR=NO'"
  dbConnection.Open()
  dbDataAdapter = New OleDb.OleDbDataAdapter("Select * From " & "[" & strWorksheet & "$]", dbConnection)
  dbDataAdapter.Fill(dtDataTable)
  strCellValue = dtDataTable.Rows(intRow(strCell)).Item(intColumn(strCell)).ToString
  dbConnection.Close()

End Function

with

Private Function intRow(ByVal strCell As String) As Integer

  intRow = CInt(System.Text.RegularExpressions.Regex.Replace(strCell, "[A-Z]", "")) - 1

End Function

and

Private Function intColumn(ByVal strCell As String) As Integer

    Dim intI As Integer
    Dim strColumn As String

    strColumn = System.Text.RegularExpressions.Regex.Replace(strCell, "[0-9]", "")
    intColumn = 0
    For intI = 0 To strColumn.Length - 1
      intColumn += (Asc(Mid(strColumn, strColumn.Length - intI, 1)) - 64) * CInt(Math.Pow(26, intI))
    Next
    intColumn -= 1

  End Function

The last 2 functions converts only the "cell-address" in Excel (e.g. "C4") to the column and row for the data-table (e.g. C==2 and 4==3).

Problem: If a cell-value in Excel is formated as date and the value in this cell is not a date (e.g. the string "Hello"), the value is assumed correct, means strCellValue="Hello". If the value is a number and so, the cell-value is a valid date (e.g. "2009.03.21"), an empty string is assumed, means strCellValue=""

Any idea why? Thank you very much.
Christian

Solved: Writing an Excel table to a DataTable / The values from Excel-cells with "date"-format are not assumed [modified]

TheSolid21-Mar-09 21:56

TheSolid

21-Mar-09 21:56

Hello,

I have solved the problem myself:

The ConnectionString must modified like this:

dbConnection.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; " & _
      "Data Source=" & strDateiname & ";" & "Extended Properties='Excel" & _
      "8.0;HDR=NO;IMEX=1;'"

The "IMEX=1;" string tells the driver, that it should "convert" mixed formated cell-values (e.g. number, string, date,...) as text.

That's it.

Regards,
Christian

modified on Sunday, March 22, 2009 4:02 AM

about MDI child form.

p_m_kanthi21-Mar-09 3:03

p_m_kanthi

21-Mar-09 3:03

how to make the form as MDI child in visual studio 2008?

Re: about MDI child form.

DaveAuld21-Mar-09 3:20

Re: about MDI child form.

21-Mar-09 3:20

You first need to have an MDI Parent form. set a forms IsMdiContainer property to True (Form1)

From the Form1, set the Child forms (Form2) parent and show it e.g.

<br />
Dim ChildForm as new Form2<br />
ChildForm.MdiParent = Me<br />
ChildForm.show()<br />

The easiest way to see this is start a new project and add MDI Parent Form, inspect the code and see how its done.

Dave
Who am I?: http://www.bebo.com/daveauld/

nazimghori21-Mar-09 7:56

21-Mar-09 7:56

first of all set form1 property of ismdicontainer to true

then place menustrip
in that write menu items as form2
now double click on form2 menu item write there below code..:-

form2.MdiParent = Me
        form2.Show()

Problem with check box

nazimghori21-Mar-09 2:57

21-Mar-09 2:57

hello every one

I want to insert the chekbox.text value like(YES/NO) on click of checkbox in listview..

for that my code is :-

If Me.chbox1.Checked = True Then
Me.chbox1.Text = "Yes"
Else
Me.chbox1.Text = "No"
End If
but this changes the value of checkbox.text every time...

so please help so that the value of text is Yes when i click checkbox and No when nothing is clicked....
Smile | :)

DaveAuld21-Mar-09 3:38

21-Mar-09 3:38

In the listview itemchecked event put;

<br />
if e.item.checked then e.item.text = "Yes" else e.item.text = "No"<br />

Dave
Who am I?: http://www.bebo.com/daveauld/

nazimghori21-Mar-09 4:05

21-Mar-09 4:05

hi i have done the same thing

f Me.chbox1.Checked = True Then
Me.chbox1.Text = "Yes"
Else
Me.chbox1.Text = "No"
End If

but this is not working every time the text value of checkbox changes
when again i go in edit mode...

so please help....

tech60321-Mar-09 5:52

tech603

21-Mar-09 5:52

The below code worked for me, are you specifying in your code that this should run when the check box is changed?

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
If CheckBox1.Checked = True Then
CheckBox1.Text = "Yes"
Else
CheckBox1.Text = "No"
End If

End Sub

Hope that helps

Matthew Vass
QA Analyst
mvass@hostmysite.com
HostMySite.com

DaveAuld21-Mar-09 6:25

21-Mar-09 6:25

He is talking about a check box in a listview.

I am a bit confused about exactly what his issue is.

Both the code you supplied for check boxes and the code i supplied for check boxes in listitems does as he has requested.

So need clarity on his issue.

Dave
Who am I?: http://www.bebo.com/daveauld/

nazimghori21-Mar-09 7:50

21-Mar-09 7:50

hello

for clearence i m sending my code:-

i had set checkbox text property to "YES/NO"

Me.chbox1.Checked = True Then

                   Me.chbox1.Text = "Yes"
               Else
                   Me.chbox1.Text = "No"

               End If
  Dim str As String = "insert into spoke_mast(area_numb,area_code,area_name,area_alias,area_select,area_tpemct) values ('" + Me.txt3.Text + "','" + Me.txt4.Text + "','" + Me.txt1.Text.ToUpper + "','" + Me.txt2.Text.ToUpper + "','" + Me.chbox1.Text + "','" + Me.cmbbox1.Text + "')"
               obj.strexecutesql(str)

where obj.strexecutesql is a function in class

but this code doesnt work it changes the text from "YES/NO" to either "YES" or "NO"
whic should happen...
so please suggest me what to do??
Smile | :)

nazimghori21-Mar-09 7:59

21-Mar-09 7:59

i m sorry the last few lines were written wrong it should be

which should not happen...
so please suggest me what to do??
Smile Smile Smile

instead
whic should happen.....
so please suggest me what to do??

DaveAuld21-Mar-09 11:05

21-Mar-09 11:05

Ok,

The code is doing what you are asking to do, but i think i now know what you are trying to do.

You want to insert 'Yes' or 'No' into the SQL string based on whether the checkbox is checked or not.

If that is the case then;

<br />
Dim tempString as String = ""<br />
If Me.chbox1.Checked Then tempString = "Yes" else tempString = "No"<br />
<br />
Dim str As String = "insert into spoke_mast(area_numb,area_code,area_name,area_alias,area_select,area_tpemct) values ('" + Me.txt3.Text + "','" + Me.txt4.Text + "','" + Me.txt1.Text.ToUpper + "','" + Me.txt2.Text.ToUpper + "','" + tempString + "','" + Me.cmbbox1.Text + "')"<br />
<br />
obj.strexecutesql(str) <br />

Dave
Who am I?: http://www.bebo.com/daveauld/

nazimghori21-Mar-09 18:23

Re: Problem with check box [modified]

21-Mar-09 18:23

hello

the solution you gave works well and good for add..

thanks for all..

but when i want to update the items in listview i use to double click on that particular record of listview...and update it

for that my code is:-

Me.chbox1.Text = Me.lst1.SelectedItems(0).SubItems(4).Text

this brings the value of listview to checkbox

now what happens is the value of checkbox.text changes from "Yes/No" to "Yes" or "No"

instead it should not change...and should remain "Yes/No" only

please suggest what to do....
Smile | :)

DaveAuld21-Mar-09 21:54

21-Mar-09 21:54

Again, your question is not good and it is not clear what you are trying to do.

Of course the checkbox text is changing, that is what the code is telling it to do. i.e. it is being set to whatever subitem(4).text value is.

Can't help you without you starting to write better questions!

Dave
Who am I?: http://www.bebo.com/daveauld/

modified on Sunday, March 22, 2009 4:25 AM

nazimghori21-Mar-09 22:58