Re: show the Name of ID datagridView cell0 to cell1 - C# Discussion Boards

Re: Is it possible to update content of an xml file in DropBox using DropBox API?

2-Jul-21 8:51

I want to update an existing XML file in DropBox without uploading and replacing a new file. Is it possible using DropBox API?

Dave Kreskowiak2-Jul-21 19:08

Dave Kreskowiak

2-Jul-21 19:08

After a quick look at the documentation for the API, found here[^], no, you can't.

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Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

How to add frame and Label controls at the same time by clicking a button in Xamarin?

Alex Dunlop1-Jul-21 6:44

Re: How to add frame and Label controls at the same time by clicking a button in Xamarin?

1-Jul-21 6:44

Hi I want to add Label and Farme controls in a way that Label's text is placed inside the Frame and the Frame size is changed based on text lenght. Actually, I want to add this XAML code by clicking a button:

<StackLayout x:Name="MyStack">
                        <Frame BackgroundColor="GreenYellow" CornerRadius="5" Padding="5">
                            <Label Text="Just For Test" FontAttributes="Bold" FontSize="Medium" />
                        </Frame>
                    </StackLayout>

between these code:

XML

<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MReport.TabbedMainPage">
    
    <!--Pages can be added as references or inline-->
    <ContentPage Title="New Report" IconImageSource="NewReport.png" BackgroundImageSource="blue_windows.jpg">
        <StackLayout Margin="5">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="10*"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>
                <ScrollView>
                    <StackLayout x:Name="MyStack">


                        <!--Labels and Frames should be added here programmatically every time the button clicked-->
                    </StackLayout>
                </ScrollView>
                <Button Grid.Row="1" Text="Add New Item" Clicked="Button_Clicked" />
            </Grid>
            <Button Grid.Row="1" Text="Send" />
        </StackLayout>
    </ContentPage>
    <ContentPage Title="Report History" IconImageSource="History.png" BackgroundImageSource="blue_windows.jpg" />
    <ContentPage Title="Messages" IconImageSource="Message.png" BackgroundImageSource="blue_windows.jpg"/>

</TabbedPage>

I tried this:

private async void Button_Clicked(object sender, EventArgs e)
       {
           MyStack.Children.Add(new Frame { CornerRadius = 5, BackgroundColor = Color.Azure});
           MyStack.Children.Add(new Label { Text = time_text[0].ToString() });
           MyStack.Children.Add(new Label { Text = time_text[1].ToString(), FontAttributes = FontAttributes.Bold, FontSize = Device.GetNamedSize(NamedSize.Medium, typeof(Label)) });
       }

But it cannot add text inside the Frame.
Please help me.

modified 1-Jul-21 12:51pm.

Gerry Schmitz1-Jul-21 7:20

Re: How to add frame and Label controls at the same time by clicking a button in Xamarin?

1-Jul-21 7:20

You create the Frame; you add the labels to the Frame; THEN you add the Frame to the StackLayout. (Or maintain a Frame reference.)

You're just adding everything to the StackLayout.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Alex Dunlop1-Jul-21 7:27

show the Name of ID datagridView cell0 to cell1

1-Jul-21 7:27

Ok, Solved. Thanks. Big Grin | :-D

modified 1-Jul-21 13:53pm.

remiki1-Jul-21 0:21

remiki

1-Jul-21 0:21

hi, i have a datagridview where i get the Ids and the amount in the first and second column,
but the third column should show me a function code for example compared to the

dataGridView2.Rows [dvd] .Cells [0] .Value //of the first collone

but, it displays them to me at the bottom instead of that evening on the same line

but, it displays them to me at the bottom instead of that evening on the same line
here is the code

void gab2relik()
        {
            cnx = new SqlConnection(db.RXcon);
            try
            {
                cnx.Open();
            }
            catch
            {
                MessageBox.Show("Erreure lors de la Connexion");
            }
            if (dataGridView2.Rows.Count>0)
            {
                for (int dvd = 0; dvd < dataGridView2.Rows.Count; dvd++)
                {
                    
                    string ct = "select grade from fction inner join person on person.id= fction.id where  id ='" + dataGridView2.Rows[dvd].Cells[0].Value + "'";
                    commd222 = new SqlCommand(ct);
                    commd222.Connection = cnx;
                    try
                    {
                        SqlDataReader d = commd222.ExecuteReader();
                        d.Read();
                        DataGridViewRow Row = (DataGridViewRow)dataGridView2.Rows[0].Clone();
                        Row.Cells[2].Value = d["grade"].ToString();
                        d.Close();
                        dataGridView2.Rows.Add(Row);
                    }
                    catch (Exception tt)
                    {
                        MessageBox.Show(tt.Message.ToString());
                    }
                    finally
                    {

                    }
                }
            
           
            }

modified 1-Jul-21 6:33am.

Re: show the Name of ID datagridView cell0 to cell1

Richard Deeming1-Jul-21 0:46

Richard Deeming

1-Jul-21 0:46

remiki wrote:

string ct = "select grade from fction inner join person on person.id= fction.id where  id ='" + dataGridView2.Rows[dvd].Cells[0].Value + "'";

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.

Everything you wanted to know about SQL injection (but were afraid to ask) | Troy Hunt[^]
How can I explain SQL injection without technical jargon? | Information Security Stack Exchange[^]
Query Parameterization Cheat Sheet | OWASP[^]

Beyond that, you need to update your code to store the value in the expected row, rather than adding a new row at the bottom.

You should also stop storing connections in class-level fields. Instead, create them when they're required, and wrap them in using blocks to ensure they are always disposed of properly.

void gab2relik()
{
    if (dataGridView2.Rows.Count == 0) return;
    
    using (var conn = new SqlConnection(db.RXcon))
    using (var cmd = new SqlCommand("SELECT grade FROM fction INNER JOIN person ON person.id = fction.id WHERE fction.id = @ID", conn))
    {
        // TODO: Specify the correct data type and size for the parameter:
        var pID = cmd.Parameters.Add("@ID", SqlDbType.VarChar);
        
        try
        {
            conn.Open();
        }
        catch
        {
            MessageBox.Show("Erreure lors de la Connexion");
            return;
        }
        
        foreach (DataGridViewRow row in dataGridView2.Rows)
        {
            pID.Value = row.Cells[0].Value ?? DBNull.Value;
            row.Cells[2].Value = cmd.ExecuteScalar();
        }
    }
}

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

Re: show the Name of ID datagridView cell0 to cell1

remiki1-Jul-21 1:31

remiki

1-Jul-21 1:31

Thank you alot, it works

Re: show the Name of ID datagridView cell0 to cell1

OriginalGriff1-Jul-21 1:02

OriginalGriff

1-Jul-21 1:02

That's some odd code ... but ...

Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'

The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'

Which SQL sees as three separate commands:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';

A perfectly valid SELECT

SQL

DROP TABLE MyTable;

A perfectly valid "delete the table" command

SQL

--'

And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

When you've fixed that through your whole app, start looking at that code.
Why are you reading each grade separately? Just issue one SQL command and read the lot - use a DataAdapter and read it all into a DataTable - then use that data to fill each row.
What you are doing is causing a heck of a lot of work for both your system and the DB Server, and you aren't even checking to see if any matching row exists!
You aren't disposing - or even closing - the connection: put that in a using block and teh system will "tidy up" behind you.
Your finally block is irrelevant, since you don't do anything in it!

And ... why are you adding rows to the DGV that you are using to limit how many times you go round the loop? That will never end until something somewhere fails - and then you will get message box after message box because it's in a try...catch inside the loop!

How to count Label controls count in Xamarin?

Alex Dunlop29-Jun-21 4:56

Re: How to count Label controls count in Xamarin?

29-Jun-21 4:56

Hi,
I want to write a code like this that runs perfectly in WinForms:

int count = 0;
            foreach (Control c in this.Controls)
            {
                if (c.GetType() == typeof(Label))
                    if (((Label)c).BackColor == Color.Red)
                        count++;
            }

But in Xamarin, I cannot use Control class. There is no namespace for it. How can I do the same in Xamarin?

Richard Deeming29-Jun-21 5:24

Richard Deeming

29-Jun-21 5:24

Your WinForms code would be better written as:

int count = 0;
foreach (Label l in this.Controls.OfType<Label>())
{
    if (l.BackColor == Color.Red)
    {
        count++;
    }
}

Or simply:

int count = this.Controls.OfType<Label>().Count(l => l.BackColor == Color.Red);

Xamarin forms doesn't have a similar concept. You might be able to do something similar by walking the visual tree - eg:
the urban canuk, eh: VisualTreeHelper for Xamarin.Forms[^]

However, it would almost certainly be better to use MVVM concepts to achieve your goal.

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

Passing parameter from one page to another

Alex Dunlop28-Jun-21 6:59

28-Jun-21 6:59

Hi,
I'm working on Xamarin project. I want to pass a parameter from one page to another.
I used this code for one of pages:

public TabbedMainPage(string parameter)
{
    InitializeComponent();
    On<Android>().SetToolbarPlacement(ToolbarPlacement.Bottom);
    On<Android>().SetIsSmoothScrollEnabled(false);
    lbl01.Text = parameter;
}

App.xaml.cs:

public App()
{
    InitializeComponent();

    MainPage = new TabbedMainPage();
}

I have error under

TabbedMainPage

in App.xaml.cs
How can I solve that error?

Gerry Schmitz28-Jun-21 7:02

28-Jun-21 7:02

MainPage = new TabbedMainPage( <parameter> );

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Alex Dunlop28-Jun-21 7:08

28-Jun-21 7:08

I wrote MainPage = new TabbedMainPage(<parameter>);
But it has error under <parameter>);

Gerry Schmitz28-Jun-21 7:29

28-Jun-21 7:29

You're supposed to supply your "own" parameter; the <parameter> is a "place holder"; you don't actually enter it.

Why did you define a parameter in your constructor when you don't know how to use it?

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Alex Dunlop28-Jun-21 7:34

28-Jun-21 7:34

I tried it. My parameter name is "parameter". I used MainPage = new TabbedMainPage(parameter);
but it has error under parameter

Gerry Schmitz28-Jun-21 8:02

28-Jun-21 8:02

Where did you "define" parameter? Since it's a string, you could use a literal; e.g. "xxx". (Don't code "xxx"; it's just an example).

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Richard Andrew x6428-Jun-21 14:23

Richard Andrew x64

28-Jun-21 14:23

It would be a good idea to actually say what the error is. That might help people to help you.

The difficult we do right away...
...the impossible takes slightly longer.

Richard MacCutchan28-Jun-21 21:13

Richard MacCutchan

28-Jun-21 21:13

You have defined your constructor as public TabbedMainPage(string parameter), so it is expecting a string, which you then post into lbl01.Text. So you need something like:

public App()
{
    InitializeComponent();

    MainPage = new TabbedMainPage("This is the text that will appear in lbl01");
}

Alex Dunlop29-Jun-21 4:53

29-Jun-21 4:53

I solved it.

private async void Button_Clicked(object sender, EventArgs e)
        {
            var result = await Navigation.ShowPopupAsync(new popup01());
            lbl01.Text = result.ToString();
        }