VB.Net, Can anybody straighten me out on accessing one form's controls from another form

Can anybody straighten me out on accessing one form's controls from another form

Author	Message
Berna #1 / 7	Can anybody straighten me out on accessing one form's controls from another form I've isolated what my problem down to the simplest example. I've got two forms: Form1 and Form2. Form1 has a text box TextBox1 and shows Form2 when it loads. Form 2 has a button. When you press the button Form2, all I want to do is increment the value in the text box on Form 1. The book I'm staring at and some posts suggest the following code should wor Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim a As Integer Dim n As New Form1() 'this is the problem I suspect a = n.text1.Text a = a + 1 n.text1.Text = a End Sub However, what really seems to happen is the New creates a new instance of Form1 and I update that form. What I want to do is get a reference to the original Form1. I've noticed that in the book I'm using, the code actually reads "Dim n as New Form1" but when I enter this the IDE adds "()". For the moment I got around this by defining a public form variable in a module, setting it to "me" when Form1 loads, and using that everywhere. I'm not finding this a satisfying solution and don't understand how original code would ever work. Obviously I'm missing something simple and it is literally keeping me awake at nights. Any ideas? Thanks, Bill
Sun, 05 Dec 2004 12:37:04 GMT

Berna #2 / 7	Can anybody straighten me out on accessing one form's controls from another form Well, it looks like I answered my own question, but I can't believe there isn't a better way. This microsoft article below suggests you take the approach I took and define a global variable or define some ugly shared variables and a shared property in the form. UGLY. Isn't there some way to just find my initial form by name or something? While overall I really like .net and they have cleaned up vast tracks of inconsistency, a few simple things are now a pain in the butt. Anybody got a better way to do this? http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_v... art/html/vbtchWorkingWithMultipleFormsInVisualBasicNETUpgradingToNET.asp
Sun, 05 Dec 2004 12:57:53 GMT

Robert Christia #3 / 7	Can anybody straighten me out on accessing one form's controls from another form Overload new() on form2 to public sub new(f as form1) create form2 from form 1 with dim f2 as new form2(me) Quote: > Well, it looks like I answered my own question, but I can't believe there isn't > a better way. > This microsoft article below suggests you take the approach I took and define a > global variable or define some ugly shared variables and a shared property in > the form. UGLY. Isn't there some way to just find my initial form by name or > something? > While overall I really like .net and they have cleaned up vast tracks of > inconsistency, a few simple things are now a pain in the butt. > Anybody got a better way to do this? > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_v... > art/html/vbtchWorkingWithMultipleFormsInVisualBasicNETUpgradingToNET.asp
Sun, 05 Dec 2004 13:27:33 GMT

wl #4 / 7	Can anybody straighten me out on accessing one form's controls from another form Hi Benahl, A better way would be to create an event delegate on form 2 (OnGetValue (byref value as integer). Assign this eventhandler to a method of form1 (addhandler) and call the event (raiseevent) in form2. This way, when you need form2 in another application, you just have to set the eventhandler to some other method, without having to change anything in form2. Wim Quote: > Well, it looks like I answered my own question, but I can't believe there isn't > a better way. > This microsoft article below suggests you take the approach I took and define a > global variable or define some ugly shared variables and a shared property in > the form. UGLY. Isn't there some way to just find my initial form by name or > something? > While overall I really like .net and they have cleaned up vast tracks of > inconsistency, a few simple things are now a pain in the butt. > Anybody got a better way to do this? > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dv_v... > art/html/vbtchWorkingWithMultipleFormsInVisualBasicNETUpgradingToNET.asp
Sun, 05 Dec 2004 13:30:04 GMT

Philli #5 / 7	Can anybody straighten me out on accessing one form's controls from another form The original code doesn't cover what you are looking for and may have been written from .Net beta. If your Form1 is your startup object and calls Form2 then Form1 has a reference to Form2. Now Form2 wants a reference to Form1. My suggestion is to add "Public mfrmParent As Form1" to Form2 class. After creating an instance of Form2 "aForm2.frmParent = me" records a reference for Form1 to Form2. . The reason for doing so on Form2 is it acts like a property (which you could code it as if you wished) and allows Form2 to address anything in Form1. Also the variable name is instructive and doesn't need a seperate module to work. Alternatively in Form2 add an overload New procedure: Public mfrmParent As Form1 Public Sub New(ByVal frmParent As Form) Me.new() mfrmParent = frmParent End Sub Now if you use "dim n as new Form2(Me)" you have created a single instance of Form2 with knowledge of it's parent Form1. Quote: > I've isolated what my problem down to the simplest example. I've got two > forms: Form1 and Form2. Form1 has a text box TextBox1 and shows Form2 when it > loads. Form 2 has a button. When you press the button Form2, all I want to do > is increment the value in the text box on Form 1. > The book I'm staring at and some posts suggest the following code should wor > Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As > System.EventArgs) Handles Button1.Click > Dim a As Integer > Dim n As New Form1() 'this is the problem I suspect > a = n.text1.Text > a = a + 1 > n.text1.Text = a > End Sub > However, what really seems to happen is the New creates a new instance of Form1 > and I update that form. What I want to do is get a reference to the original > Form1. I've noticed that in the book I'm using, the code actually reads "Dim n > as New Form1" but when I enter this the IDE adds "()". > For the moment I got around this by defining a public form variable in a > module, setting it to "me" when Form1 loads, and using that everywhere. I'm > not finding this a satisfying solution and don't understand how original code > would ever work. > Obviously I'm missing something simple and it is literally keeping me awake at > nights. > Any ideas? > Thanks, Bill
Sun, 05 Dec 2004 13:33:12 GMT

Bill Bernah #6 / 7	Can anybody straighten me out on accessing one form's controls from another form Phillip, wil, Robert, Excellent suggestions all. Thanks for helping me get up to speed here. For anyone searching in the future, it seems that Mansfield's "Visual Basic .Net Weekend Crash Course" has a problem with the session 6 example having been written for the beta release and not quite working in the commercial release. - Bill Quote: > The original code doesn't cover what you are looking for and may have been > written from .Net beta. > If your Form1 is your startup object and calls Form2 then Form1 has a > reference to Form2. Now Form2 wants a reference to Form1. > My suggestion is to add "Public mfrmParent As Form1" to Form2 class. After > creating an instance of Form2 "aForm2.frmParent = me" records a reference > for Form1 to Form2. > . > The reason for doing so on Form2 is it acts like a property (which you could > code it as if you wished) and allows Form2 to address anything in Form1. > Also the variable name is instructive and doesn't need a seperate module to > work. > Alternatively in Form2 add an overload New procedure: > Public mfrmParent As Form1 > Public Sub New(ByVal frmParent As Form) > Me.new() > mfrmParent = frmParent > End Sub > Now if you use "dim n as new Form2(Me)" you have created a single instance > of Form2 with knowledge of it's parent Form1. > > I've isolated what my problem down to the simplest example. I've got two > > forms: Form1 and Form2. Form1 has a text box TextBox1 and shows Form2 > when it > > loads. Form 2 has a button. When you press the button Form2, all I want > to do > > is increment the value in the text box on Form 1. > > The book I'm staring at and some posts suggest the following code should > wor > > Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As > > System.EventArgs) Handles Button1.Click > > Dim a As Integer > > Dim n As New Form1() 'this is the problem I suspect > > a = n.text1.Text > > a = a + 1 > > n.text1.Text = a > > End Sub > > However, what really seems to happen is the New creates a new instance of > Form1 > > and I update that form. What I want to do is get a reference to the > original > > Form1. I've noticed that in the book I'm using, the code actually reads > "Dim n > > as New Form1" but when I enter this the IDE adds "()". > > For the moment I got around this by defining a public form variable in a > > module, setting it to "me" when Form1 loads, and using that everywhere. > I'm > > not finding this a satisfying solution and don't understand how original > code > > would ever work. > > Obviously I'm missing something simple and it is literally keeping me > awake at > > nights. > > Any ideas? > > Thanks, Bill
Sun, 05 Dec 2004 14:30:57 GMT

Philli #7 / 7	Can anybody straighten me out on accessing one form's controls from another form I have now Learnt with threading it is important to use Invoke and Delegate when accessing objects controlled from another thread. Have a look at http://www.codenotes.com/do/articles/article?articleID=515. Note text line wrapping has to be fixed when pasting the code and the second source replaces several procedures in the first. Quote: > Phillip, wil, Robert, > Excellent suggestions all. Thanks for helping me get up to speed here. > For anyone searching in the future, it seems that Mansfield's "Visual Basic > .Net Weekend Crash Course" has a problem with the session 6 example having > been written for the beta release and not quite working in the commercial > release. > - Bill > > The original code doesn't cover what you are looking for and may have been > > written from .Net beta. > > If your Form1 is your startup object and calls Form2 then Form1 has a > > reference to Form2. Now Form2 wants a reference to Form1. > > My suggestion is to add "Public mfrmParent As Form1" to Form2 class. After > > creating an instance of Form2 "aForm2.frmParent = me" records a reference > > for Form1 to Form2. > > . > > The reason for doing so on Form2 is it acts like a property (which you > could > > code it as if you wished) and allows Form2 to address anything in Form1. > > Also the variable name is instructive and doesn't need a seperate module > to > > work. > > Alternatively in Form2 add an overload New procedure: > > Public mfrmParent As Form1 > > Public Sub New(ByVal frmParent As Form) > > Me.new() > > mfrmParent = frmParent > > End Sub > > Now if you use "dim n as new Form2(Me)" you have created a single instance > > of Form2 with knowledge of it's parent Form1. > > > I've isolated what my problem down to the simplest example. I've got > two > > > forms: Form1 and Form2. Form1 has a text box TextBox1 and shows Form2 > > when it > > > loads. Form 2 has a button. When you press the button Form2, all I > want > > to do > > > is increment the value in the text box on Form 1. > > > The book I'm staring at and some posts suggest the following code should > > wor > > > Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As > > > System.EventArgs) Handles Button1.Click > > > Dim a As Integer > > > Dim n As New Form1() 'this is the problem I suspect > > > a = n.text1.Text > > > a = a + 1 > > > n.text1.Text = a > > > End Sub > > > However, what really seems to happen is the New creates a new instance > of > > Form1 > > > and I update that form. What I want to do is get a reference to the > > original > > > Form1. I've noticed that in the book I'm using, the code actually reads > > "Dim n > > > as New Form1" but when I enter this the IDE adds "()". > > > For the moment I got around this by defining a public form variable in a > > > module, setting it to "me" when Form1 loads, and using that everywhere. > > I'm > > > not finding this a satisfying solution and don't understand how original > > code > > > would ever work. > > > Obviously I'm missing something simple and it is literally keeping me > > awake at > > > nights. > > > Any ideas? > > > Thanks, Bill
Mon, 06 Dec 2004 11:43:48 GMT

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