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Re: Easy way programmatically select step by step button.

9-Jan-22 7:17

I'm guessing that you want to create a "wizard".

Simple Wizard for WinForms

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OriginalGriff9-Jan-22 9:38

Re: Easy way programmatically select step by step button.

9-Jan-22 9:38

No, it's for ALS / MDN patients (think about how Stephen Hawking selected words / phrases on his computer with only the one "button" he could press).

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Gerry Schmitz9-Jan-22 21:11

Re: Easy way programmatically select step by step button.

9-Jan-22 21:11

If it was that serious, I would look into gaze tracking / interactions. And I think it depends on the subject.

OriginalGriff9-Jan-22 21:18

Re: Easy way programmatically select step by step button.

9-Jan-22 21:18

I suspect it's a school project rather than a serious application: his skill level looks to be pretty low ATM.

Richard Deeming9-Jan-22 21:30

Richard Deeming

9-Jan-22 21:30

OriginalGriff wrote:
MDN patients

I didn't realise users of the Mozilla Developer Network[^] were classed as "patients". Poke tongue | ;-P

(I suspect you meant "MND", or "get me another coffee".)

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Re: Easy way programmatically select step by step button.

OriginalGriff9-Jan-22 21:58

bind a gridview and a listbox to a database

9-Jan-22 21:58

It's the last one ... Sigh | :sigh:

Message Removed

5-Jan-22 9:21

Laomedeia

5-Jan-22 9:21

Message Removed

modified 6-Jan-22 3:14am.

steven_noppe5-Jan-22 2:03

steven_noppe

5-Jan-22 2:03

Hello,

I have a simple question I think, but do not seem to find an answer easily Smile | :)

I have a lisbox and a gridview. Both are connected to a database through the design editor.
visualisation works, but now I want to show only the items in the gridview which are connected to a chosen item in the listbox.

I already set the listbox to visualize a name and the value member to have the "primary key".

Now I want to show only the items in the gridview who are connected to this primary key.
Inside the design editor I can add a query like this :

SELECT pkID, ProductieVolgorde, Stuknr, Rolnr, AantalMeters, DatumTijd, Status, fkPO 
FROM dbo.tblDoek1
WHERE fkPO = @What do I place here?

how do I link the chosen value member of the listbox to this fkPO in the query?

Is there somewhere a simple tutorial on how to link a database fully inside the Design editor?

thanks in advance

Gerry Schmitz5-Jan-22 5:26

5-Jan-22 5:26

You use the SelectedIndexChanged event of the ListBox, in conjunction with the SelectedItem (as "Type") property, to sync the ListBox with the GridView (filter).

ListBox.SelectedIndexChanged Event (System.Windows.Forms) | Microsoft Docs

RobertSF7-Jan-22 10:47

RobertSF

7-Jan-22 10:47

Hi, there. So you have a listbox with, for example, country names, and you want to display in the datagridview a list only of the cities of the country selected in the listbox. You actually don't need a whole new query for this. This is called a master-detail relationship (so you can google for that), or more precisely, a one-to-many relationship.

In the designer, you can set up a relation between the two tables. Then you use the table adapter to load the tables as usual. But you set the data source of the datagridview to the same binding source of the listbox, with the data member set to the relation. So, the master binding source points to the data table in the data set. Then the detail binding source points to the relation in the master binding source.

On the form, once you set the bindings this way, it's all automatic. When the selected item in the list box changes, the datagridview automatically updates.

A different method is this. Set the master binding source to its master table, and the detail binding source to its detail table. Then, when the selected value in the listbox changes, intercept the event and set a filter on the detail binding source (which is bound to the datagridview).

The first method is mostly done in designer, and the second is done mostly in code. You could create a query for this purpose, but these two methods would generally be more efficient. I hope this helps!

modified 7-Jan-22 18:08pm.

steven_noppe11-Jan-22 22:31

steven_noppe

11-Jan-22 22:31

Hello RobertSF,

that was the asnwer I was looking for thanx!

Will any changes in the gridview be adapted in the database too this way?

edit : I spoke too early Smile | :)

when I change the selection in my listbox the application hangs

modified 12-Jan-22 5:53am.

RobertSF12-Jan-22 12:37

RobertSF

12-Jan-22 12:37

If the grid is edited, yes, you can propagate the changes to the database. It won't happen automatically. You'll first have to call EndEdit on the binding source and possibly first on the grid, and then use either a table adapter update method or the dataset update method.

It's pretty rare for applications to hang, in my experience. They more often crash with exceptions, though they can also get stuck in infinite loops. Try working with the debugger and going line by line.

Or google for "master detail two datagridview" and try it with two grids instead of listbox and a grid. I don't think I can post link, but the full title of the Microsoft document is "Walkthrough: Creating a Master/Detail Form Using Two Windows Forms DataGridView Controls"

Is there a way to improve this code?

RobertSF12-Jan-22 13:33

RobertSF

12-Jan-22 13:33

Maybe this will help. I created an Access database with two tables.

Table: Countries
-string: CountryName

Table: Cities
-string: CountryName
-string: CityName

No relationships created between the two tables. Entered three countries (USA, Canada, Mexico), and three cities in each country.

In Visual Studio, created a new dataset with the two tables from the database. Here, I did create a relationship, linking the Cities table to the Countries table by the CountryName column. The relationship, which exists only in Visual Studio, is called Countries_Cities.

Then I created a form and dropped a ListBox into the form. Setting the DataSource to the Countries table (you must drill down in Designer) automatically creates the countriesBindingSource. Then I set the DisplayMember to CountryName. Here are the binding setting for the ListBox.

// listBox1
// 
this.listBox1.DataSource = this.countriesBindingSource;
this.listBox1.DisplayMember = "CountryName";

Then I dropped a DataGridView into the form. When I clicked the button to select the Data Source, my choices were countriesBindingSource and Other Data Sources. Drill down into countriesBindingSource and select the Countries_Cities relationship. This will automatically create the countriesCitiesBindingSource and will auto-populate the DataGridView with two columns, CountryName and CityName. You can delete the CountryName column. Here are the binding values for the DataGridView.

// dataGridView1
// 
this.dataGridView1.DataSource = this.countriesCitiesBindingSource;

This is all designer code, so you need not code anything so far. Now run the application. The form should appear, showing the countries in the List Box, but only the cities for the selected country in the DataGridView.

Click on the other countries in the ListBox, and the DataGridView should automatically show only the cities for the selected country. I hope this helps. This stuff can be pretty crazy-making because there are few practical examples to follow.

Richard A Knox4-Jan-22 8:06

Richard A Knox

4-Jan-22 8:06

This is a program I have been tinkering with for my daughter to help her budget her finances. I understand that there are programs out there, but I wanted something to do and decided to play around with do this.

I am working on the income section, which has income coming in either weekly, semi monthly, bimonthly, monthly or yearly. What I am showing is the weekly section and I am curious as to whether there is a better method, which there usually is to what I am attempting to accomplish.

The "ds.Tables[0].Rows[i][0].ToString()" brings in the test verbiage for whether its weekly, monthly, whatever.

The "f" variable in the for loop is a numerical response provided by the user as to how far out they which to forecast their budget. 4 weeks, 6 weeks, 8 weeks and so forth.

If there is more detail needed, please let me know.

//============= Begining of Weekly (52) ==========
                        if (ds.Tables[0].Rows[i][0].ToString() == "Weekly (52)")
                        {
                        var date = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);

                        for (int x = 1; x < 7; x++)
                            {
                              if (ds.Tables[0].Rows[i][1].ToString() != date.ToString("ddd"))
                                {
                                   
                                DateTime newdate = date.AddDays(1);
                                date = newdate;
   
                                }
                                else
                                {
                                    for (int n = 0; n <= ((4*f)-1); n++)
                                        {
                                        list.Add(date);
                                        DateTime newdate = date.AddDays(7);
                                        date = newdate;
                                          
                                        }

                                    break;
                                }
                            }
                        }
                        //============= Ending of Weekly (52) ==========

Thank you,
Richard
Disable Vet
Grandfather
Pain in the @ss

Re: Is there a way to improve this code?

Gerry Schmitz4-Jan-22 12:25

Re: Is there a way to improve this code?

4-Jan-22 12:25

You refer to your daughter as "the user"? Unless she's a CEO, she could probably get by with Excel; they even have "budget templates".

Richard Deeming4-Jan-22 22:20

Richard Deeming

4-Jan-22 22:20

I'd start with something like this:

private static DateTime NextWeekDay(DateTime date, string expectedDayOfWeek, DateTimeFormatInfo dateFormat)
{
    int expectedDayIndex = Array.IndexOf(dateFormat.AbbreviatedDayNames, expectedDayOfWeek);
    if (expectedDayIndex != -1)
    {
        int dayOfWeek = (int)date.DayOfWeek;
        if (dayOfWeek != expectedDayIndex)
        {
            int daysToAdd = expectedDayIndex - dayOfWeek;
            if (daysToAdd < 0) daysToAdd += 7;
            date = date.AddDays(daysToAdd);
        }
    }
    
    return date;
}

DateTime today = DateTime.Today;
DataTable dt = ds.Tables[0];
DateTimeFormatInfo dateFormat = DateTimeFormatInfo.GetInstance(CultureInfo.CurrentCulture);

foreach (DataRow row in dt.Rows)
{
    string budgetType = row[0].ToString();
    switch (budgetType)
    {
        ...
        case "Weekly (52)":
        {
            DateTime date = today.AddDays(1 - today.Day);
            
            string expectedDayOfWeek = row[1].ToString();
            date = NextWeekDay(date, expectedDayOfWeek, dateFormat);
            
            int max = (4 * f);
            for (int n = 0; n < max; n++)
            {
                list.Add(date);
                date = date.AddDays(7);
            }
            break;
        }
        ...
    }
}

Further optimisation may be possible depending on what the rest of the code looks like.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Is there a way to improve this code?

Pete O'Hanlon4-Jan-22 22:49

Pete O'Hanlon

4-Jan-22 22:49

If the code works and it is clear to you, then don't go changing it just for the sake of changing it. I often hear people talking about "improving" code, but they are vague on what improvement actually means in this case. Sure, there are some minor optimisations that jump out but whether or not they are worth putting in is debatable.

Advanced TypeScript Programming Projects

CSV File Access - Error Msg : the process cannot access the file used by another process

The Golden Man4-Jan-22 7:26

The Golden Man

4-Jan-22 7:26

Hello Guys,

I have a CSV file which looks something like this :

Entry Price, Quantity, SL Level, TP Level, Side
nothing, nothing, nothing, nothing, nothing

As you can see, using the code below, I try to make sure if I have the file already, otherwise I create one with the same content above :

if (!File.Exists(path))
{
    sw = File.AppendText(path);
    
    if (writeHeaders) {
    sw.WriteLine("Entry Price, " + "Quantity, " + "SL Level, " + "TP Level, " + "Side");
    writeHeaders = false;
}

sw.WriteLine("nothing" + "," + "nothing" + "," + "nothing" + "," + "nothing" + "," + "nothing");
sw.Close();

}

but the if a position is taking place, I want to replace "nothing" with real values, depends on each column :

if (File.Exists(path) && PositionAccount.Quantity > 0)
{
    List<string> newLines = new List<string>();
    string[] existingLines = File.ReadAllLines(path, encode);
    
    foreach (string line in existingLines)
    {
        string[] columns = line.Split(new char[] {','});
        
        string EntryPrice = columns[0];
        string Qtty = columns[1];
        string SSLevel = columns[2];
        string TTPLevel = columns[3];
        string PSide = columns[4];
        
        EntryPrice = EntryPrice.Replace("nothing", PositionAccount.AveragePrice.ToString());
        Qtty = Qtty.Replace("nothing", QtyMini.ToString());
        SSLevel = SSLevel.Replace("nothing", LongSL.ToString());
        TTPLevel = TTPLevel.Replace("nothing", LongTP.ToString());
        PSide = PSide.Replace("nothing", "Long");
        
        columns[0] = EntryPrice;
        columns[1] = Qtty;
        columns[2] = SSLevel;
        columns[3] = TTPLevel;
        columns[4] = PSide;
        
        string newLine = string.Join(",", columns);
        newLines.Add(newLine);
    }

    File.WriteAllLines(path, newLines);
}

both above codes are working perfectly, and doing what they are supposed to do, EXCEPT THAT, when I try to READ the csv file from another strategy, it shows an Errors Message of "Error Msg : the process cannot access the file used by another process" and it disables everything.

I really tried all possible ways that I came across in all forums to fix this problem, but I was not able to do it, I think that the file is not closed from the first opening this is why it shows this message, so I tried

using ()

, I tried FileSharing, File Access, I tried FileStream, I tried StreamReader, but in some of them I was not able to readalllines and writealllines, as well I was not able to read only line[1] for example, and modify it and replace it.

using (mystream = File.Open(path, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
{

}

Can you plz tell me how to fix it ? Thank you

Re: CSV File Access - Error Msg : the process cannot access the file used by another process

Gerry Schmitz4-Jan-22 12:16

4-Jan-22 12:16

You're doing a "read all", then a "write all", both to the same "path".

"Simple" requires that you "write" to a different file than the one you're reading.

Other scenarios are more advanced.

About records

Super Lloyd3-Jan-22 9:12

3-Jan-22 9:12

I am still puzzling out the benefit of record. So far I am underwhelmed.

The only cool thing that caught my eyes is the with syntax for making mutated copies. That's cool. Though I wonder why it's available only to records.

Other than that, meh..
I mean it's cool to have Equals(), ==, !=, ToString() automatically implemented as well I guess. But it's presented like an "additional benefit" whereas it seems to me to be the only benefit, as far as I can tell..

Anyone care to sing the praise of records?
I am starting to introduce some record in my own home code base. But it increasingly feels like an exercise in futily.. Sigh | :sigh:

(to be fair, an effortless exercise, just one keyword Laugh | :laugh:

)

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modified 3-Jan-22 15:20pm.

OriginalGriff3-Jan-22 20:28

3-Jan-22 20:28

Thanks for bring this up; I wasn't aware they existed.

That's interesting: an immutable class with a value comparison.
That's basically a value type that can be inherited from, which is a big limitation - there are times when it would have been nice to inherit from int to add specific functionality without having to encapsulate it and manually build the comparison operators (since classes always default to a reference equality) - a record does a property-by-property value comparison for you, and is by default immutable. Nice.

Not sure what I'll use them for yet, but they are well worth remembering for future projects.

Good question! Thumbs Up | :thumbsup:

Super Lloyd3-Jan-22 20:31

3-Jan-22 20:31

You're welcome! Smile | :)

Sing the praise when you do! Big Grin | :-D

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Super Lloyd3-Jan-22 20:33

3-Jan-22 20:33

I might be missing the benefit because records, I suspect, target things like data manipulation / EntityFramework, which is as far as possible from what I am doing now, both at work and home....

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Super Lloyd3-Jan-22 21:07