passing a value that maybe null to a dialog form - C# Discussion Boards

It works, not sure if its correct or not

13-Apr-15 9:58

I figured out to add a new record to the table, but I can't figure out how to update an existing record.
I'm not sure how to proceed here.
I tried Add again, but it bombed in the entity part.
This is my first time doing this using the DAL without binding, actually I have no clue how to bind it either.

private int data_Save(Guid pValue)
{
    int dwRCode = 2;

    // Fetch the Data, and write it to the Customer
    string m_businessName = BusinessNameTextBox.Text.Trim();
    string m_firstName = firstNameTextBox.Text.Trim();
    string m_lastName = lastNameTextBox.Text.Trim();                    

    StoreContext context = new StoreContext();
    if (Guid.Empty == pValue)
    {
        Customer c = new Customer
        {
            BusinessName = m_businessName,
            FirstName = m_firstName,
            LastName = m_lastName
        };   

        // Insert the new record in Customers
        context.Customers.Add(c);
        dwRCode = context.SaveChanges(); // returns 1 if successful, 0 if failed
    }
    else
    {
        // Update the record in Customers
        // So how do you update a record?
        // Do I have to load the record, update the context, and then write it?
        dwRCode = context.SaveChanges(); // returns 1 if successful, 0 if failed     

     }
     return dwRCode;
}

jkirkerx13-Apr-15 12:10

Printing graphics in C# with sizes in mm

13-Apr-15 12:10

I wrote the delete record, and figured update was similar in code.
I'm sure about the return value from save, it the int is the record added or if 1 = added successfully, and 0 = updated successfully

private int data_Save(Guid pValue)
{
    int dwRCode = 2;

    // Fetch the Data, and write it to the Customer
    string m_businessName = BusinessNameTextBox.Text.Trim();
    string m_firstName = firstNameTextBox.Text.Trim();
    string m_lastName = lastNameTextBox.Text.Trim();                    

    StoreContext context = new StoreContext();
    if (Guid.Empty == pValue)
    {
        Customer c = new Customer
        {
            BusinessName = m_businessName,
            FirstName = m_firstName,
            LastName = m_lastName
        };   

        // Insert the new record in Customers
        context.Customers.Add(c);
        dwRCode = context.SaveChanges(); // returns 1 if successful, ? if failed
    }
    else
    {
        // Update the record in Customers
        var customer = context.Customers.Where(i => i.ID == pValue).FirstOrDefault();
        if (customer != null)
        {
            context.Customers.Attach(customer);

            customer.BusinessName = m_businessName;
            customer.FirstName = m_firstName;
            customer.LastName = m_lastName;

            dwRCode = context.SaveChanges(); // returns 0 if successful, ? if failed<br />
        }                 

    }
    return dwRCode;
}

Member 1050678613-Apr-15 8:21

Member 10506786

13-Apr-15 8:21

Never printed graphics before, I am stuck in the beginning.
I've got some graphics elements, like rectangles and circles. They show OK on the screen. Now I need to print them keeping proper scaling: all sizes are in millimetres. And first question is: how do I print a rectangle 100 x 100 mm? What size on paper does this rectangle have:

gr.DrawRectangle(Pens.Black, 100, 100, 100, 100)?

I know it must be linked somehow to default printer's resolution, but I am lost: could not find anything useful in help.
(using C# in Visual Studio 2012)

Thank you

Re: Printing graphics in C# with sizes in mm

OriginalGriff13-Apr-15 8:26

OriginalGriff

13-Apr-15 8:26

Set the Graphics.PageUnit[^] to mm:

gr.PageUnit = GraphicsUnit.Millimeter;

And all subsequent drawing references will use mm instead of pixels regardless of the device being drawn onto. Note that this won't necessarily be accurate on a monitor, where the system doesn't really know what size it is anyway! Laugh | :laugh:

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

passing a value that maybe null to a dialog form

jkirkerx13-Apr-15 8:13

Re: passing a value that maybe null to a dialog form

13-Apr-15 8:13

I have a dialog form, you can add or edit customers, the owner of the project choose to use a Guid value.
How do I write the public dialog function to accept a null value or a valid Guid?
I tried the ?, but got a conversion error, not suite sure what it means.
Then I get Guid is non nullable

public dialog_customerDetails(Guid? position)
{
    InitializeComponent();
    if (position != null)
   {
       _position = position; 
   }        
}

Then in the calling form

Guid m_value= new Guid(item.SubItems[0].Text);
dialog_customerDetails dialog_CD = new dialog_customerDetails(m_value); // For Edit

if (new dialog_customerDetails(null).ShowDialog() == DialogResult.OK) // For Add

OriginalGriff13-Apr-15 8:22

OriginalGriff

13-Apr-15 8:22

Guid is a valuetype, which means that it can't contain a null value - only references can be null.
When you declare it as

Guid? m_value;

You are declaring it as a different type altogether, so you can't assign a Guid? type value directly into a Guid - and you can;t convert a null from a Guid? to a Guid value anyway!

Instead of null, use Guid.Empty instead:

public dialog_customerDetails(Guid position)
{
    InitializeComponent();
    if (position != Guid.Empty)
   {
       _position = position;
   }
}

And use Guid throughout instead of Guid?

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Re: passing a value that maybe null to a dialog form

jkirkerx13-Apr-15 8:41

Tree class recommendation

13-Apr-15 8:41

oh It's that simple, I starting to get c# better now.
Guid.Empty

Say, could you look at my previous post below, post 3 on the way I loaded the data from the DAL?
If you have free time.
Just wanted to confirm that I'm on the right track before I write more of it.

ENVDTE2 Question

Kevin Marois13-Apr-15 8:03

Kevin Marois

13-Apr-15 8:03

The documentation for this is obscure and all over the place. I'm trying to get the solution open in THIS instance of VS:

using EnvDTE;
using EnvDTE80;
using System;
using System.Windows.Forms;

namespace EnvDTE_Test
{
    class Program
    {
        static void Main(string[] args)
        {
            EnvDTE80.DTE2 dte2 = (EnvDTE80.DTE2)System.Runtime.InteropServices.Marshal.GetActiveObject("VisualStudio.DTE.11.0");

            try
            {
                Project prj = dte2.Solution.Projects.Item(1);

                Projects prjs;

                string msg, msg2 = "Global Variables:";

                msg = "FileName: " + prj.FileName;
                msg += "\nFullName: " + prj.FullName;
                msg += "\nProject-level access to " + prj.CodeModel.CodeElements.Count.ToString() + " CodeElements through the CodeModel";

                prjs = prj.Collection;
                msg += "\nThere are " + prjs.Count.ToString() + " projects in the same collection.";
                msg += "\nApplication containing this project: " + prj.DTE.Name;

                if (prj.Saved)
                    msg += "\nThis project hasn't been modified since the last save.";
                else
                    msg += "\nThis project has been modified since the last save.";
                msg += "\nProperties: ";

                foreach (Property prop in prj.Properties)
                {
                    msg += "\n  " + prop.Name;
                }

                foreach (String s in (Array)prj.Globals.VariableNames)
                {
                    msg2 += "\n  " + s;
                }

                MessageBox.Show(msg, "Project Name: " + prj.Name);
                MessageBox.Show(msg2);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
    }
}

I previously opened 2 other instances of VS, and this gives me the first one, not the none this code is running in.

Anyone know what I'm doing wrong?

Thanks

If it's not broken, fix it until it is

DaveyM6913-Apr-15 6:05

DaveyM69

13-Apr-15 6:05

Hi,

I need to create a data structure that is very tree like that operates similar to a directory structure. For example:

/ch - will add "ch" to root
/ch/01/config - will add "01" to ch from above and "config" to 01
/ch/02/insert - will add "02" to ch from first line and "insert" to 02
/ch/01/mix/01 - will add "mix" to 01 from second line and "01" to mix
/config/chlink - will add "config" to root and "chlink" to config

which will result in a Tree layout like:

root->ch    ->01    ->config
                    ->mix   ->01
            ->02    ->insert
    ->config->chlink

I have been playing with this for a while now and just can't get anything I write to function in this way. If anyone could point me in the right direction it would be much appreciated!

Dave

Binging is like googling, it just feels dirtier.
Please take your VB.NET out of our nice case sensitive forum.
Astonish us. Be exceptional. (Pete O'Hanlon)

BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

Eddy Vluggen13-Apr-15 8:58

13-Apr-15 8:58

DaveyM69 wrote:
If anyone could point me in the right direction it would be much appreciated!

You'd need a class that can hold a reference to itself (the parent) and a collection of its childeren. Like below;

using System;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;

class Program
{
    public class Folder
    {
        Collection<Folder> _children;
        public Folder Parent { get; private set; }
        public string Name { get; set; }
        public Collection<Folder> Children { get { return _children; } }

        private Folder(Folder parent, string name)
        {
            _children = new Collection<Folder>();
            Parent = parent;
            Name = name;
        }

        public static Folder CreateNewRoot()
        {
            return new Folder(null, "Root");
        }

        public Folder CreateFolder(string name)
        {
            var result = new Folder(this, name);
            this.Children.Add(result);
            return result;
        }

        public override string ToString()
        {
            Folder currentFolder = this;

            var pathBuilder = new StringBuilder();
            while (currentFolder != null)
            {
                pathBuilder.Insert(0, currentFolder.Name);
                pathBuilder.Insert(0, '/');
                currentFolder = currentFolder.Parent;
            }

            return pathBuilder.ToString();
        }
    }

    static Folder CreatePath(Folder startingFolder, string path)
    {
        string[] pathParts = path.Split(new[] { '/' }, StringSplitOptions.RemoveEmptyEntries);
        Folder currentFolder = startingFolder;
        for (int i = 0; i < pathParts.Length; i++)
        {
            string targetName = pathParts[i];
            // does current folder hold our target?
            Folder targetFolder = null;
            if (0 != currentFolder.Children.Count())
                targetFolder = currentFolder.Children.FirstOrDefault(f => f.Name == targetName);
            if (null == targetFolder)
            {
                // it don't exist yet
                targetFolder = currentFolder.CreateFolder(targetName);
            }
            // on to the next one
            currentFolder = targetFolder;
        }

        return currentFolder;
    } 

    static void DumpFolderToConsole(Folder fromWhere)
    {
        Console.WriteLine(fromWhere);
        foreach (Folder folder in fromWhere.Children)
        {
            DumpFolderToConsole(folder);
        }
    }

    static void Main(string[] args)
    {
        Folder root = Folder.CreateNewRoot();
        CreatePath(root, @"/ch");
        CreatePath(root, @"/ch/01/config");
        CreatePath(root, @"/ch/02/insert");
        CreatePath(root, @"/ch/01/mix/01");
        CreatePath(root, @"/config/chlink");

        DumpFolderToConsole(root);
        Console.ReadLine();
    }
}

Outputs

/Root
/Root/ch
/Root/ch/01
/Root/ch/01/config
/Root/ch/01/mix
/Root/ch/01/mix/01
/Root/ch/02
/Root/ch/02/insert
/Root/config
/Root/config/chlink

Some remarks; the example also creates sub-folders if required, even if the starting list was shorter than the resulting dump. It does not contain provisions for other stuff yet, like files. If you want such a structure (complete with a byte[] for the file-class), then there's an example in an article[^] I wrote.

--edit
You asked for a class, not for code; I'd recommend the TreeNode, as it contains a lot what you'd want out of the box. Another advantage thereof would be that it'd be very easy to visualize in a TreeView.

---- edit
PO'H - I unchecked the "Use Markdown formatting" checkbox for you. This fixed the odd layout issues in your code block.

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

modified 14-Apr-15 8:47am.

DaveyM6913-Apr-15 12:46

DaveyM69

13-Apr-15 12:46

Thanks Eddy, I'll try this tomorrow Thumbs Up | :thumbsup:

It's actually to hold and look up against OSC[^] addresses for a particular device. I don't need all the wild card stuff thankfully so with what you've given me I should be close.

Thanks again Smile | :)

Eddy Vluggen13-Apr-15 12:54

13-Apr-15 12:54

You're welcome, and good luck Smile | :)

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]

BillWoodruff13-Apr-15 14:20

BillWoodruff

13-Apr-15 14:20

I think Eddy V. has given you a great code-example. If you end up needing a very fancy Node structure that keeps track of ancestors, descendants, etc., this is a good resource: [^].

I came across this code for 'Node a few years ago when reading this thread on StackOverflow: [^] which has several code examples for different types of Tree data-structures in C#.

cheers, Bill

«To kill an error's as good a service, sometimes better than, establishing new truth or fact.» Charles Darwin in "Prospero's Precepts"

BillWoodruff13-Apr-15 13:22

BillWoodruff

13-Apr-15 13:22

For this kind of code sample, I wish I had more than one up-vote Smile | :)

thanks, Bill

«To kill an error's as good a service, sometimes better than, establishing new truth or fact.» Charles Darwin in "Prospero's Precepts"

Eddy Vluggen13-Apr-15 21:51

13-Apr-15 21:51

Thanks

DaveyM6914-Apr-15 8:26

DaveyM69

14-Apr-15 8:26

Well thanks again Eddy, it's done the job brilliantly with only a few minor tweaks to allow for use in my situation!
Awesome Smile | :)

Eddy Vluggen14-Apr-15 9:02

14-Apr-15 9:02

You're welcome, and thanks Smile | :)