[c#]linq sort a stringarray into vars

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I have an Array of strings. Each string contains multiple vars separated by a ",". I remember years ago when I did VB.NET there was a way to LINQ sort an array into corresponding vars, select which ones you need and use them however you like. For example:

Dim facultyQuery = From member In members
                          Let column = member.Split(","c)
                          Let name = column(0)
                          Let points = CInt(column(1))
                          Select name, points
                          Order By name

For Each member In facultyQuery
            strTemp = member.name
            Exit For
        Next

That was a simple LINQ sort for a drop down I made in VB. Now I'm looking to do the same in C#. My goal is to sort the data, take out what I don't need and put what I need into DataGridView control for display. Here's a sample of one of the strings:

C#

CAR_Sales_Default,2,0,2,0,00:24:56,00:00:00,0,69,-LWC_BG:#cc0000,-LCB_BG:#00cc00

I need to sort out the name, the 3rd number, the 2 times and their corresponding background and put that into a DataGridView. How can I do that using LINQ in C#?

Edit:
Got it working using something like this

C#

char[] splitChars = new char[] { ',' };

            var query = from data in tr
                        let columns = data.Split(splitChars, StringSplitOptions.None)
                        select new
                        {
                            qNames = columns[0].Substring(0, columns[0].Length - 6),
                            totCallW8 = Int32.Parse(columns[3]),
                            longW8InCall = columns[5],
                            longW8CallBack = columns[6],
                            BGtrLWC = columns[9].Substring(8),
                            BGtrLCB = columns[10].Substring(8),
                        }
                            into qSort
                            orderby qSort.qNames
                            select qSort;

            foreach (var result in query)
            {
                if (result.qNames.Contains(system))
                {
                    
                    dataGridView1.Rows.Add(result.qNames, result.totCallW8, result.longW8InCall, result.longW8CallBack);

                    dataGridView1.CurrentCell = dataGridView1.Rows[count].Cells[2];

                    dataGridView1[2, dataGridView1.CurrentRow.Index].Style.BackColor = ColorTranslator.FromHtml(result.BGtrLWC);
                    dataGridView1[3, dataGridView1.CurrentRow.Index].Style.BackColor = ColorTranslator.FromHtml(result.BGtrLCB);

                    count++;
                }
            }

What I have tried:

I could use a for loop and manually split them and add them to the GridView but that will take too long. My first approach to even displaying all the data in a ListView was a for loop and that made the run time very bad.

Posted 6-Feb-16 1:19am

User 12277010

Updated 7-Feb-16 14:55pm

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BillWoodruff 6-Feb-16 10:19am

If you want speed, you need to get the data into a form you can de-serialize into a List of Classes or Structs, and then do binding using that list.

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Sascha Lefèvre · Accepted Answer · 2016-02-06T01:51:00

If you want to use the same approach, this is how you could do it in C#:

C#

// this declaration as a class member:
static char[] splitChars = new char[] { ',' };

// just some sample data:
string[] rows = new string[] { "name2,1,2,3", "name1,3,4,5" };

var query = from row in rows
            let columns = row.Split(splitChars, StringSplitOptions.None)
            select new
            {
                name = columns[0],
                points = Int32.Parse(columns[1]),
            }
            into results
            orderby results.name
            select results;

foreach (var result in query)
{
    Console.WriteLine(String.Format("Name: {0}, Points: {1}", result.name, result.points));
}

But you might consider using a CSV reader instead. Here's an excellent one: A Fast CSV Reader[^]

Edit:
I missed the part that you want to display the result in a DataGridView. The fastest way to get there would be this:

C#

MydataGridView.DataSource = query.ToList();

However, if you want to modify the values in the DGV and then read them back into somewhere I would recommend using either a DataTable or a regular class for the results instead of the anonymous type constructed by the compiler in my sample above - so something like this instead:

C#

public class ResultRow
{
    public string Name { get; private set; } // non-editable in DGV
    public int Points { get; set; }          // editable in DGV

    public ResultRow(string name, int points)
    {
        Name = name;
        Points = points;
    }
}

// as a class member:
List<ResultRow> ResultsList;


var query2 = from row in rows
             let columns = row.Split(splitChars, StringSplitOptions.None)
             select new ResultRow(columns[0], Int32.Parse(columns[1])) into results
             orderby results.Name
             select results;

ResultsList = query2.ToList();

MyDataGridView.DataSource = ResultsList;

Edit 2 (after comment):
Sample code to add cell coloring based on values read from your source data - maybe not 100% what you want to achieve but I think you will get the idea:

C#

public partial class Form2 : Form
{
    static char[] splitChars = new char[] { ',' };

    BindingList<ResultRow> ResultsBindingList;

    public class ResultRow
    {
        public string Name { get; private set; } // non-editable in DGV
        public int Points { get; set; }          // editable in DGV
        public Color CellColor { get; private set; }

        public ResultRow(string name, int points, Color cellColor)
        {
            Name = name;
            Points = points;
            CellColor = cellColor;
        }
    }

    public Form2()
    {
        InitializeComponent();

        string[] rows = new string[] { "name2,1,2,3,#cc0000", "name1,3,4,5,#00cc00" };

        var query = from row in rows
            let columns = row.Split(splitChars, StringSplitOptions.None)
            let name = columns[0]
            let points = Int32.Parse(columns[1])
            let color = System.Drawing.ColorTranslator.FromHtml(columns[4])
            select new ResultRow(name, points, color) into results
            orderby results.Name
            select results;

        ResultsBindingList = new BindingList<ResultRow>(query.ToList());

        MyDataGridView.DataSource = ResultsBindingList;

        MyDataGridView.Columns["CellColor"].Visible = false;

        MyDataGridView.CellFormatting += MyDataGridViewCellFormatting;
    }

    private void MyDataGridViewCellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
    {
        e.CellStyle.BackColor = (Color)MyDataGridView["CellColor", e.RowIndex].Value;
    }

    private void AddRowButtonClick(object sender, EventArgs e)
    {
        ResultsBindingList.Add(new ResultRow("", 0, Color.Yellow));
    }
}

OriginalGriff · Accepted Answer · 2016-02-06T02:02:00

Linq won't speed up the process that much - it's a loop as well, but it's a "deferred execution" loop that happens behind the scenes when the data is actually required instead of when the original query code is executed.

And if the run time is "very bad" when loading your data into any display control, that's normally a sign that you are trying to display far too much information. Never load a control with more than 100 rows, and preferably never with more than 20 or so - above that it's both slow and unusable for the user as he can't find what he needs to look at in the morass of the other data. Page it, filter it, but never just throw it all at the user!

[c#]linq sort a stringarray into vars

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