Please help me I stucked while dead line is going to be end

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I created a new project.It has 1 class and 1 form
class "GridView.vb"
form "Form1.vb"

class GridView.vb has following code

VB

Public Shared ConnectionString As String
Public Shared Query As String
Public Shared FormName As String
Public Shared GridViewName As String
Public Shared Function ExecuteQuery()
    Dim con As New SqlConnection
    con.ConnectionString = ConnectionString
    con.Open()
    Dim da As SqlDataAdapter = New SqlDataAdapter(Query, con)
    Dim dt As New DataTable
    da.Fill(dt)
    FormName.GridViewName.DataSource = dt
End Function

and Form1.vb has follwoing code into button1

VB

GridView.FormName = Me.Text & ".vb"
GridView.GridViewName = "DataGridView1"
GridView.ConnectionString = "Server = CHATTHA; Database = Test; User Id = sa; Password = pak123"
GridView.Query = "Select * from Table1"
GridView.ExecuteQuery()

In class this code line is not working

VB

FormName.GridViewName.DataSource = dt

It says GridViewName is not member of string.

Please help me and guide

Posted 1-Dec-15 22:19pm

Rizwan Chattha

Updated 2-Dec-15 1:54am

phil.o

v4

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Comments

StM0n 2-Dec-15 6:43am

Are you aware of the fact, that <<String>> has no property <<DataSource>>... are you looking for <<GridView.DataSource = dt>>?

Rizwan Chattha 2-Dec-15 6:58am

I want to make this class later dll file. So later i don,t want to change this class and i also want to use this class in other projects with many other forms with different form names.

Rizwan Chattha 2-Dec-15 6:55am

Yes i know string does not have property but i don,t know about how to access gridview properties into class. when i write
Form1.DataGridView1.DataSource=dt" it works. but i want to replace Form1 with some variable to use this class in any other projects without changing class again.

Rizwan Chattha 2-Dec-15 6:56am

"Form1.DataGridView1.DataSource=dt" works but i want to use this class for other projects without any changing in class.

3 solutions

Solution 3

You try to access the objects by using their names (I hope it's explained good enough).
In your case FormName does NOT Access the Form itself. You have to search in the application.openforms-Collection for the Form-object to get the Form itself, you are using.
With the GridViewName it is the same. Here you have to search in the Form.controls-Collection for the right object and refer to it.

Now you perhaps could acces the objects like you want.

But for me it isn't clear why you want to do it like this. I think that there are easier and better understandable ways to get nearly the same goal ...

Posted 2-Dec-15 1:47am

Ralf Meier

Comments

Rizwan Chattha 2-Dec-15 8:05am

Purpose is to shorten code and instead of writing code again and again just use class which is made already.

Ralf Meier 2-Dec-15 8:15am

I understood your Intension - did you understand OOP ?
A Form is a kind of class - you could build it one time like you need it and after this you could instance it (like every control) like you want.

But you could also walk your way. It isn't impossible - but it is not easy.
Did you understood what I have written in my solution ?

Rizwan Chattha 2-Dec-15 8:25am

If way i am choosing is difficult then what is easy way to acheive goal.

Rizwan Chattha 2-Dec-15 8:17am

I shall be very thankfull to you if you post easy example which you mentioned above.
I tried application.openforms-collection
but still i am stuck before this i have not used application.openforms-collection.
Please give some example.

Solution 1

Quote:
FormName.GridViewName.DataSource = dt

I guess this should be

VB

DataSource = dt

instead.

Posted 2-Dec-15 0:43am

CPallini

Comments

Rizwan Chattha 2-Dec-15 6:52am

No it does not works

CPallini 2-Dec-15 6:56am

You should assign the DataSource properties of the actual GridView object.

Rizwan Chattha 2-Dec-15 6:59am

"Form1.DataGridView1.DataSource=dt" works but i want to use this class for other projects without any changing in class.

Rizwan Chattha 2-Dec-15 7:00am

I want to make this class later dll file. So later i don,t want to change this class and i also want to use this class in other projects with many other forms with different form names and also with different GridView names.

Rizwan Chattha 2-Dec-15 7:02am

So what changing should i do in class that it shall work for any form name and grid view with any name.

Rizwan Chattha 2-Dec-15 7:07am

Please ask if my point is not cleared.

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CHill60 · Accepted Answer · 2015-12-02T01:36:00

Solution 2

Based on your comment

Quote:
I want to make this class later dll file. So later i don,t want to change this class and i also want to use this class in other projects with many other forms with different form names and also with different GridView names.

You will need to pass the control through to the class method if you want to use it for any form.

E.g. a method like this (simple example for text box)

VB.NET

Public Sub UpdateControl(ByVal cc As Control)
    If cc Is Nothing Then
        MessageBox.Show("Form or control not defined")
        Return
    End If

    Try
        cc.Text = cc.Parent.Name
    Catch ex As Exception
        MessageBox.Show("Error {0}", ex.Message)
    End Try
End Sub

could be called like

VB.NET

Private Sub btnForm2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnForm2.Click
    myC.UpdateControl(f2.Controls.Find("tbForm2", True)(0))
End Sub

Or you could make the control a property of the class.
Note I've used Try-Catch (not the best example of its use) in case the control passed does not have the property I'm trying to update.

[EDIT] - using the OP's code (NB untested and no checking or error handling)

C#

Public Shared ConnectionString As String
Public Shared Query As String
Public Shared FormName As String
Public Shared GridViewName As String
Public Shared GridView as Control
Public Shared Function ExecuteQuery()
    Dim con As New SqlConnection
    con.ConnectionString = ConnectionString
    con.Open()
    Dim da As SqlDataAdapter = New SqlDataAdapter(Query, con)
    Dim dt As New DataTable
    da.Fill(dt)
    GridView.DataSource = dt
End Function

And in the form

GridView.FormName = Me.Text & ".vb"
GridView.GridViewName = "DataGridView1"
GridView.ConnectionString = "Server = CHATTHA; Database = Test; User Id = sa; Password = pak123"
GridView.Query = "Select * from Table1"
GridView.GridView = Me.Controls.Find("DataGridView1", True)(0)
GridView.ExecuteQuery()

[EDIT 2 - OP is struggling...]
In your GridView.vb try the following

C#

Public Shared ConnectionString As String
Public Shared Query As String
Public Shared FormName As String
Public Shared GridViewName As String
Public Shared Function ExecuteQuery(GridView as DataGridView)
    Dim con As New SqlConnection
    con.ConnectionString = ConnectionString
    con.Open()
    Dim da As SqlDataAdapter = New SqlDataAdapter(Query, con)
    Dim dt As New DataTable
    da.Fill(dt)
    GridView.DataSource = dt
End Function

And on your form where you are calling this put

C#

GridView.FormName = Me.Text & ".vb"
GridView.GridViewName = "DataGridView1"
GridView.ConnectionString = "Server = CHATTHA; Database = Test; User Id = sa; Password = pak123"
GridView.Query = "Select * from Table1"
GridView.ExecuteQuery(Me.DataGridView1)

Posted 2-Dec-15 1:36am

CHill60

Updated 2-Dec-15 4:05am

v3

Comments

Rizwan Chattha 2-Dec-15 8:15am

I tested below code and it gives error object reference not set to an object.
Dim a As Control
a.Text = a.Parent.Name
MsgBox(a.Text)

CHill60 2-Dec-15 8:28am

Because you haven't assigned a value to a!

Rizwan Chattha 2-Dec-15 8:32am

I want to assign currently open form name to a and this code is in class? what should i write in class.

Rizwan Chattha 2-Dec-15 8:28am

Please provide tested example. I shall be thankfull to you if you provide easy example.

CHill60 2-Dec-15 8:31am

I've put an easy example in my solution - just substitute your control names for the ones I've used

CHill60 2-Dec-15 8:37am

I've updated my solution.
You cannot assign the form name to a Control - Form name is a string not a control.

Rizwan Chattha 2-Dec-15 8:36am

In this code where should i change. Please assing some value in below code and post edited code
Dim a As Control
a.Text = a.Parent.Name
MsgBox(a.Text)

CHill60 2-Dec-15 8:39am

You need to assign a value to the variable a - e.g. a = Me.Controls.Find("xxxxx", True)(0)
Where xxxxx is whatever you have called the control on your form.
See the code in my solution where I pass the control into the class

Rizwan Chattha 2-Dec-15 8:44am

myC.UpdateControl(f2.Controls.Find("tbForm2", True)(0))

f2 is not working. I put Me instead of f2 and again it is giving error

Rizwan Chattha 2-Dec-15 8:46am

error is "Reference to a non shared member requires an object reference."

Rizwan Chattha 2-Dec-15 8:46am

error is "Reference to a non shared member requires an object reference."

CHill60 2-Dec-15 8:47am

f2 is the name of the form in my example - you don't have a form called f2.
What is the error that is being produced? Bear in mind you do not have a control called "tbForm2", nor do you have an object called myC. It was meant to be an example of what to do, not a fully worked and tested solution. I updated my solution using your variable names etc.

Rizwan Chattha 2-Dec-15 8:51am

i replaced Form1 instead of tbForm2 and i replace GridView class instead of myC. and i also solved this error error "Reference to a non shared member requires an object reference." using public shared function. but now it is giving new error

Rizwan Chattha 2-Dec-15 8:54am

I am using this line code in button2
GridView.UpdateControl(Me.Controls.Find("Form1", True)(0))

but when i press button2 it gives runtime
error "index was outside the bounds of array"

CHill60 2-Dec-15 8:59am

"Form1" is the name of the form, not the control - you need to pass through the instance of the Gridview so use "DataGridView1" as per my edited solution

Rizwan Chattha 2-Dec-15 9:02am

I solved one part of problem. I got form name by using below code
GridView.UpdateControl(Me.Controls.Find("DataGridView1", True)(0))

Result of above line is that it tells this controls is used in form1. Am i right?

CHill60 2-Dec-15 9:07am

If this code was run on Form1 then the parent of the control DataGridView1 is indeed Form1.

Rizwan Chattha 2-Dec-15 9:18am

cc.Text = cc.Parent.Name
works fine but now next is what should replace instead of Form1 in below line code.

Form1.DataGridView1.DataSource = dt

CHill60 2-Dec-15 9:21am

With GridView.DataSource = dt - have another look at my solution! I went back to it and used YOUR variable names etc.

Rizwan Chattha 2-Dec-15 9:28am

In GridView class "GridView.DataSource = dt" is not working. My GridView class code is below
cc.Text = cc.Parent.Name
MsgBox(cc.Text)
'=============================================
Dim con As New SqlConnection
con.ConnectionString = ConnectionString
con.Open()
Dim da As SqlDataAdapter = New SqlDataAdapter(Query, con)
Dim dt As New DataTable
da.Fill(dt)
Form1.DataGridView1.DataSource = dt

I used GridView.DataSource = dt instead of Form1.DataGridView1.DataSource = dt
but it is not working

CHill60 2-Dec-15 9:53am

What do mean by "not working" is there an error?
What is cc in your class - in my simple example it was the control being passed to the class.
You may need to declare GridView as a DataGridView rather than Control that I used

CHill60 2-Dec-15 10:08am

I've updated my solution again - look for everything after "EDIT 2" - it should work by just pasting into your project where you already have very similar code ... if it does not then you must tell me what the error message is in order for me to help you

Rizwan Chattha 2-Dec-15 9:20am

when i replace cc.text instead of Form1 it gives error.

Rizwan Chattha 2-Dec-15 11:22am

Yes now it is working.
I was stuck here "Public Shared Function ExecuteQuery(ByVal GridView As DataGridView)"
I did not put parameter "ByVal GridView As DataGridView".

Thanks a lot to you. You really helped me.
Thanks againg many many.

CHill60 2-Dec-15 11:24am

Glad we got there.

Rizwan Chattha 2-Dec-15 11:40am

yeah we got after hard work. Now just 3 lines code is needed to write instead of 7 lines code.
Old long code:
'Dim con As New SqlConnection
'con.ConnectionString = "Server = CHATTHA; Database = Test; User Id = sa; Password = pak123"
'con.Open()
'Dim da As SqlDataAdapter = New SqlDataAdapter("Select * from Table1", con)
'Dim dt As New DataTable
'da.Fill(dt)
'DataGridView1.DataSource = dt

New short code
Dim cs As String = "Server = CHATTHA; Database = Test; User Id = sa; Password = pak123"
Dim qr As String = "Select * from Table1"
GridView.ExecuteQuery(Me.DataGridView1, cs, qr)