.NET (Core and Framework)

13-Mar-20 23:51

It was so simple in VB, accessing other forms properties.

The main form, right after it's drawn, I want to check for a .db file and if it dosen't exist, to make visible a form (already defined) to create it the db file. (form already as always-on-top, but not visible).

After a ton of internet research, i'm still where I started. Closest I got gave me a threading error, which I've learned to work around in VB, but this, is just confusing (TechTracker.CreateDB.ActiveForm.Visible = true;)

I like how much c# is to PHP AFA structure, loops, arrays, strings. But this stuff is confusing me

Richard MacCutchan14-Mar-20 1:07

14-Mar-20 1:07

Uranium-235 wrote:
It was so simple in VB, accessing other forms properties.

The same is true in C#. Perhaps you could show your code and explain exactly where the problem lies.

Uranium-23514-Mar-20 4:37

14-Mar-20 4:37

my main.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SQLite;
using System.IO;

namespace TechTracker
{
          
    
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent();
        }


        private void Main_Load(object sender, EventArgs e)
        {
            if(!File.Exists(Directory.GetCurrentDirectory() + "\\Tracker.db"))
            {
                //yeah none of these worked
                //((CreateDB)this.Owner).Show();
                //Form CreateDBForm = CreateDB.FindForm();
                //TechTracker.CreateDB.ActiveForm.Visible = true;
                //System.Windows.Forms.Control.Invoke;
                 

            }
        }
    }
}

createDB.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace TechTracker
{
    public partial class CreateDB : Form
    {
        public CreateDB()
        {
            InitializeComponent();
            
        }
    }
}

both were made as windows forms designer. createDB is not visible by default. As you can see, if the file is not there, they choose to create it as an sqlLite (I know I still have to define it in using in createdb) database. createDB is topmost enabled and won't let the main form be accessible when it's up. That logic shouldn't be hard, i've done it with vb before. I'll later get a better method of detecting the database file (store filepath in registry, or local file). Probably even allow switching DB files in a settings dropdown. For now, this just basic code to get some of the basic functionality out of this way.

I learned VB.net from scratch using only google on trial and error. Got fairly good at it too. It's just these individual methods of c# I need to get out of the way

oh and yes, it's me from the previous post. I decided to go with sqllite instead of mysql or transactional HTTP transfer. I'm making this mainly for me for the time being, and I can just use google drive or something to sync the sqllite db file for housecall (on my laptop) or home use

thank you

Dave Kreskowiak14-Mar-20 4:58

Dave Kreskowiak

14-Mar-20 4:58

Forms are nothing but classes. So how do you create an instance of a class? You "new one up".

CreateDB createForm = new CreateDB();
createForm.ShowDialog();     // Or .Show() depending on requirements

This would be the exact same thing you do in VB.NET.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Uranium-23514-Mar-20 5:35

14-Mar-20 5:35

I remember in VB.net I would use something like My.Forms but it's been a while

Dave Kreskowiak14-Mar-20 6:30

Dave Kreskowiak

14-Mar-20 6:30

That is actually a wrapper around exactly what I posted. What you're calling "in VB.NET" is actually just a bunch of classes in a namespace that wrap this kind of functionality to maintain "backward compatibility" with older VB code.

The wrappers and extensions are not in the language itself, but is in a library of classes. Since it's all in a .NET library, you could even use the library in other languages, like C#, but I wouldn't recommend doing that. What the library does is insulate you from learning and knowing all the gritty details of how things should be done and they actually work.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Richard MacCutchan14-Mar-20 6:11

14-Mar-20 6:11

Uranium-235 wrote:
createDB is topmost enabled and won't let the main form be accessible when it's up.

You don't need Topmost, just make it a dialog so it automatically disables the calling form:

CreateDB dbCreator = new CreateDB();
DialogResult rc = dbCreator.ShowDialog();
// check rc for success etc.

Here is a really useful C# tutorial: http://www.charlespetzold.com/dotnet/index.html[^].

Uranium-23514-Mar-20 6:51

14-Mar-20 6:51

Thank you guys. I was googling for over an hour last night (phrasing?). I still have a lot to learn.

Richard MacCutchan14-Mar-20 7:02

14-Mar-20 7:02

You will never learn programming from Google or Youtube. Get yourself a decent book that will teach you properly, starting with the basics. Time spent now will pay dividends in the future.

Uranium-23514-Mar-20 20:42

14-Mar-20 20:42

I learned PHP and VB from googling. Actually I learned PHP because a game named Tribes used the zend engine and I picked up a PHP book and realized I knew the syntax better than the book. Did PHP for 10 years and made some pretty impressive stuff.

I also did some stuff in VB that was pretty advanced. But I haven't done it in a few years (like, 4?)

Once you learn many of the basics of .net, all I have left is translating it into the syntax of c#, which IMO has better structure than VB, and a structure i'm more familiar with (logic and conditions like PHP, some variables like C++, which I took in high school)

I don't think I could relearn the VB crap. I'm used to &&, ||, if() foreach loops, all in PHP. One thing I didn't like is you can't do multiple logical comparisons in switch/case, but that it rarely used in PHP

Uranium-23514-Mar-20 20:25

14-Mar-20 20:25

actually this is throwing me an error. "

Quote:
Cannot implicitly convert type 'void' to 'System.Windows.Forms.DialogResult

public partial class Main : Form
{
    public Main()
    {
        InitializeComponent();
    }


    private void Main_Load(object sender, EventArgs e)
    {
        if(!File.Exists(Directory.GetCurrentDirectory() + "\\Tracker.db"))
        {
            this.Enabled = false;

            CreateDB dbForm = new CreateDB();
            DialogResult res = dbForm.ShowDialog(); //dbform error

            if (res == DialogResult.Cancel)
                Application.Exit();
        }
    }
}

public partial class CreateDB : Form
    {
        public event EventHandler CancelPressed;
        
        public CreateDB()
        {
            InitializeComponent();
                       
        }

        private void Cancel_Click(object sender, EventArgs e)
        {
            if (CancelPressed != null)
                CancelPressed(this, EventArgs.Empty);
        }
    }

Richard MacCutchan14-Mar-20 22:10

14-Mar-20 22:10

Your CreateDB form needs to return a valid DialogResult. See Form.ShowDialog Method (System.Windows.Forms) | Microsoft Docs[^].

Uranium-23515-Mar-20 4:41

15-Mar-20 4:41

private void Cancel_Click(object sender, EventArgs e)
        {
            //if (CancelPressed != null)
            //    CancelPressed(this, EventArgs.Empty);

            return DialogResult.Cancel;
        }

I returned a DialogResult now I get

Since 'TechTracker.CreateDB.Cancel_Click(object, System.EventArgs)' returns void, a return keyword must not be followed by an object expression

and yeah I tried changing void to DialogResult and it gave me an error on the form

Richard MacCutchan15-Mar-20 4:44

15-Mar-20 4:44

The Cancel_Click is a delegate type, so it cannot return a value. It handles an event and then returns to the framework. You need to return your DialogResult from the main method of the form.

See Form.ShowDialog Method (System.Windows.Forms) | Microsoft Docs[^].

Uranium-23515-Mar-20 7:40

15-Mar-20 7:40

ok I get it, so I didn't even need cancel_click (this is a delegate, right?) at all since the DialogResult was already cancel in the form properties.

Richard MacCutchan15-Mar-20 8:00

15-Mar-20 8:00

Correct.

Uranium-2359-Apr-20 23:01

9-Apr-20 23:01

ok, been working on it, i'd figure i'd just add to this instead of making a new thread. I've been messing with SQLite.

What I want is to make a function to run the query, get row data and return it. Of course, rows are of mixed types, Using GetDataTypeName(), but storing these into an array is impossible because arrays can only be one type

is there a way to store the row data into an array? I've tried the reader row data itself, but i'm not sure i'm going about it the right way

this is the core section i'm trying. I've successfully done the query and got the data inside the function, just returning it is the problem

sqlite_cmd = sql_conn.CreateCommand();
sqlite_cmd.CommandText = sql_query;
sqlite_datareader = sqlite_cmd.ExecuteReader();

SQLLiteReader Row[];


//store reader data in an array?
    for(int i = 0; sqlite_datareader.Read(); i++)
    {
            Row[i] = sqlite_datareader;
    }

and return the row. I tried passing the reader up by reference but that was unsuccessful

My error:
Bad array declarator: To declare a managed array the rank specifier precedes the variable's identifier. To declare a fixed size buffer field, use the fixed keyword before the field type.

Uranium-23510-Apr-20 10:12

10-Apr-20 10:12

oh duh I needed to specify 'Array'

but now I get

Array SQLLiteReader Row[];
                    ^^^
                    "; expected"
                        ^
                        identifier expected

Uranium-23511-Apr-20 16:33