My DataGridView won't display data

Carlos Martinez

16y9.6kVisual Basic .NET

Hi guys I need help with my C# winform app

below/attached the code

Thanks.

--------------------------------------------------------------------------------

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.IO;

namespace ListOfRunners

{

public partial class Form1 : Form

{

//protected Runner runner;

//protected List listRunner;

public Form1()

{

InitializeComponent();

//runner = new Runner();

//listRunner = new List();

}

private void Form1_Load(object sender, EventArgs e)

{

//Runner runner = new Runner();

List listRunner = new List();

StreamReader myReader = new StreamReader("TextFile1.txt");

string line = "";

{

line = myReader.ReadLine();

if (line != null)

{

listRunner.Add(GetRunnerDetails(line));

}

} while (line != null);

myReader.Close();

var query = from r in listRunner

//orderby r.Time

//select r;

select new { r.Name, r.Time, r.Age };

dataGridView1.DataSource = query;

foreach (var item in query)

{

MessageBox.Show("Name:" + item.Name);

}

//Process each line of data to get the Participant object

private Runner GetRunnerDetails(string line)

{

Runner runner = new Runner();

line = line.Trim();

//to get the name

int delimiterIndex = line.IndexOf(" ");

runner.Name = line.Substring(0, delimiterIndex);

line = line.Replace(runner.Name, "");

line = line.Trim();

//to get age

delimiterIndex = line.IndexOf(" ");

runner.Time = int.Parse(line.Substring(0, delimiterIndex));

line = line.Replace(runner.Time.ToString(), "");

line = line.Trim();

//to get the time

runner.Age = int.Parse(line);

return runner;

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ListOfRunners

{

class Runner

{

public string Name { get; set; }

public int Time { get; set; }

public int Age { get; set; }

public int Ranking { get; set; }

public void Print()

{

Console.WriteLine("{0} {1} {2}", Name, Time, Age);

}

Jay 12 33

Hem 34 28

Umesh 22 37

Tom 21 30

Cliff 13 33

Vini 17 28

Matt 10 28

Ben 9 29

Brandon 15 14

12 Replies

Know the answer? Post it — somebody with the same question will find it here.

Howard Schuchman11y ago
How did you sort the column labeled TIME?
Bryian Tan16y ago
hello,

There is an extra right curly bracket (}) on line 91 return Group; }. remove the } . Then add the right curly bracket at the end of the AssignRanks method
Carlos Martinez16y ago
Sorry people, I forgot the error messages

this is the main error

Error 1 Expected class, delegate, enum, interface, or struct C:\Users\Numancia\Documents\Visual Studio 2010\Projects\ListOfRunners\ListOfRunners\Form1.cs 94 23 ListOfRunners

regarding this method implementation.

private static void AssignRanks(ref List list)

here is the link to the screenshots for a better look.

error 1 --> http://img87.imageshack.us/img87/7646/error1q.jpg

error 2 --.http://img146.imageshack.us/img146/1893/error2ma.jpg
Bryian Tan16y ago
hello,

What is the error message?
Carlos Martinez16y ago
Here is the update to Runner.cs

I am attaching the code again just in case.

Thanks a lot everybody again.

----------------------------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ListOfRunners
{
   class Runner
   {
   public string Name { get; set; }
   public int Time { get; set; }
   public int Age { get; set; }
   public int Ranking { get; set; }

   public void Print()
   {
   Console.WriteLine("{0} {1} {2}", Name, Time, Age);
   }

   public int CompareTo(Runner r)
   {
   return this.Time.CompareTo(r.Time);
   }
   }
}
Carlos Martinez16y ago
Hi there,

Thanks a lot Bryian Tan, your explanation makes a lot of sense.

I have some update to the application, It's almost done but I can't figure this error out.

Code is attached

below is the update to the Form1.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.IO;

namespace ListOfRunners
{
   public partial class Form1 : Form
   {
   public Form1()
   {
   InitializeComponent();
   }

   private void Form1_Load(object sender, EventArgs e)
   {

   List listRunner = new List();

   List groupSmallerThan15 = new List();
   List groupBetween15and29 = new List();
   List groupGreaterThan29 = new List();

   StreamReader myReader = new StreamReader("TextFile1.txt");
   string line = "";

   do
   {
   line = myReader.ReadLine();

   if (line != null)
   {
   listRunner.Add(GetRunnerDetails(line));
   }

   } while (line != null);

   myReader.Close();

   groupSmallerThan15 = GetGroupBasedOnAgeLimits(0, 15, listRunner);
   groupSmallerThan15 = GetGroupBasedOnAgeLimits(15, 29, listRunner);
   groupSmallerThan15 = GetGroupBasedOnAgeLimits(29, 100, listRunner);

   AssignRanks(ref groupSmallerThan15);
   AssignRanks(ref groupBetween15and29);
   AssignRanks(ref groupGreaterThan29);

   //Merge 3-List
   //=======================================================
   List mergedList = new List(groupSmallerThan15.Count + groupBetween15and29.Count + groupGreaterThan29.Count);
   mergedList.AddRange(groupSmallerThan15);
   mergedList.AddRange(groupBetween15and29);
   mergedList.AddRange(groupGreaterThan29);

   dataGridView1.DataSource = mergedList;

   }

   private static Runner GetRunnerDetails(string line)
   {
   Runner runner = new Runner();
   try
   {
   string[] token = line.Split(' ');
   runner.Name = token[0];
   runner.Time = int.Parse(token[1]);
   runner.Age = int.Parse(token[2]);
   }
   catch (Exception ex)
   {
   Console.WriteLine(ex.Message);
   }
   return runner;
   }

   private static List GetGroupBasedOnAgeLimits(int StartAge, int EndAge, List lstRunners)
   {
   List Group = new List();

   foreach (Runner R in lstRunners)
   {
   if (R.Age >= StartAge && R.Age <= EndAge) Group.Add(R);
   }

   return Group; }
   }

   private static void AssignRanks(ref List list)
   {
   int Rank = 1;
   foreach (Runner r in list)
   {
   r.Ranking = Rank;
   Rank++;
   }
   }
}
Bryian Tan16y ago
hi,

The DatGridView is expecting a typed object. The article mentioned "The ObjectQuery class represents a typed query...". On the other hand, your query return anonymous type and listRunner is defined as List type. The method .ToList() will force immediate query evaluation and return a List.

You can also use BindingSource. See below example.

....
var query = from r in listRunner
                        //orderby r.Time
                        //select r;
                        select new { r.Name, r.Time, r.Age };

BindingSource bs = new BindingSource();
            bs.DataSource = query;
            dataGridView1.DataSource = bs;

.....
Carlos Martinez16y ago
Thanks a lot, it's working now.

But can you explain me why regarding this part of the code, there is no need for query.ToList(); //convert the Enumerable to List

----------------------------------------------------
private void Form1_Load(object sender, EventArgs e)
{
ObjectQuery personNameQuery = personNameContext.PersonName;
dgvPersonName.DataSource = personNameQuery;
dgvPersonName.Columns["ID"].Visible = false;
}
----------------------------------------------------
link to the code above -->http://www.codeproject.com/KB/databa...ramework3.aspx
Bryian Tan16y ago
hello,

Change dataGridView1.DataSource = query;

to

dataGridView1.DataSource = query.ToList(); //convert the Enumerable to List
Carlos Martinez16y ago
Problem
=========================================================================
You have a list of runners and their race times and ages. Create a
program to display the runners sorted by finish time with a column showing
their finish position (ranking) within their age group.

The age groups are
0 - 15 years
16 - 29 years
30+ years

Read the following data from a column delimited (fixed field width) text file....
Name Time Age
--------------------
Steve 12 33
Tim 34 28
Mark 22 37
Tom 21 30
Cliff 13 33
Vini 17 28
Matt 10 28
Ben 9 29
Brandon 15 14

The output should look something like this, displayed in a GUI.

RACE RESULTS
Name Time Age Ranking
===== ==== === =======
Ben 9 29 1
Matt 10 28 2
Steve 12 33 1
Cliff 13 33 2
Brandon 15 14 1
Vini 17 28 3
Tom 21 30 3
Mark 22 37 4
Tim 34 28 4

Create your own, or employ any available classes, to help you solve this problem.
The program should present the results in a Windows GUI app.
Suthish Nair16y ago
That's a good point Sam..
Sam Hobbs16y ago
It will really help if youy can give us a hint about what is supposed to happen that is not happening or what is not happening that is supposed to happen or whatever.