sorting columns using particular words in c#

i have a table with a column named size which will have values big,medium and开发者_运维问答 small. wat i want is i want to sort this column in such a way that all rows with size big should come first, then rows with size medium and finally rows with size small. is there a way by which i can achieve this?

edit: it is a data table which i add to a dataset.

edit: wat if the initials of the words, in this case b,m and s, are not in alphabetical order. in that wat am i supposed to do coz i have another application as well where i'll be required to sort a column having value High, normal and low.

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Example

DataTable dt = ds.Tables[0]; 
DataView dv = new DataView(dt); 
dv.Sort = sortExpression + direction; //sortexpression will be fieldname direction will be ascending descending
GridView1.DataSource = dv;
GridView1.DataBind()

Have a look at this article: Express Yourself with Expression-based Columns

http://msdn.microsoft.com/en-us/library/ms810291.aspx

OF COURSE IT WORKS!

    DataSet myDs = new DataSet();
    DataTable myDt = new DataTable("Table1");

    myDs.Tables.Add(myDt);

    myDt.Columns.Add("Size", typeof(string));
    myDt.Columns.Add("Ranking", typeof(int), "Iif((Size)='Large', 1, Iif((Size)='Medium', 2, Iif((Size)='Small', 3, 4)))");

    DataRow myDr1 = myDs.Tables["Table1"].NewRow();
    DataRow myDr2 = myDs.Tables["Table1"].NewRow();
    DataRow myDr3 = myDs.Tables["Table1"].NewRow();
    DataRow myDr4 = myDs.Tables["Table1"].NewRow();

    myDr1["Size"] = "Large";
    myDr2["Size"] = "Medium";
    myDr3["Size"] = "Small";
    myDr4["Size"] = "Large";

    myDt.Rows.Add(myDr1);
    myDt.Rows.Add(myDr2);
    myDt.Rows.Add(myDr3);
    myDt.Rows.Add(myDr4);

    DataView myDv = new DataView(myDt);
    myDv.Sort = "Ranking";

    ultraGrid1.DataSource = myDv;

And that is the code that proves it.

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Map big, medium, small to an enum in the correct order and sort on that. Any other answer will require more information as asked for in the comments.

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If this is really as masqueraded T-SQL question, you could either use UNION (as proposed by Lukasz), or you could use a few WHEN ... THEN constructs in your ORDER BY:

SELECT *
FROM SomeTable
ORDER BY WHEN size = 'big' THEN 2 WHEN 'medium' THEN 1 ELSE 0 END

This might also work in ADO.NET, but I have not tested it:

myDataTable.DefaultView.Sort =
    "WHEN size = 'big' THEN 2 WHEN 'medium' THEN 1 ELSE 0 END";

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EDIT: David points out, that in your specific case (big, medium, small), the alphabetical sort order matches the expected ordering. In this special case, you can simply do:

ORDER BY size

Or in ADO.NET:

myDataTable.DefaultView.Sort = "size";

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If you want a simple solution (and if these values are unlikely to change), just order by the 'size' column, since the big, medium and small words are in alphabetical order :D

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Using the built-in sorting algorithm of the DataView (which is where you'd do actual sorting, not in the DataTable itself), this isn't possible, strictly speaking; there is no support for "custom" sorting, which is what you'd need. The sorting capabilities of the DataView are actually surprisingly limited, and (IIRC) it isn't even a stable sort (since it uses Array.Sort, which is documented as unstable).

Your only real option (from a GUI perspective) is to use a data display control that provides custom sorting capability, like the DevExpress XtraGrid.

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After edits by OP, it has become (somewhat) clear that we are dealing with a DataTable.

One approach to sorting the rows of a DataTable according to a "mapped value", would be to use its Select method to retrieve several arrays (one for each value) of rows:

List<DataRow> rows = new List<DataRow>();
rows.AddRange(oldTable.Select("size = 'Big'"));
rows.AddRange(oldTable.Select("size = 'Medium'"));
rows.AddRange(oldTable.Select("size = 'Small'"));

If needed, the rows can be imported into a fresh DataTable with the same schema:

DataTable newTable = oldTable.Clone();
foreach (DataRow row in rows)
{
    newTable.ImportRow(row);
}

This approach is definitely not very efficient, but it's probably about the easiest way to do this.

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Try a switch statement.

Switch(var) 
{ Case "Big":
//Append to TextBox1
//Or add to var1[]
break;
  Case "Small":
//Append to TextBox2
//Or add to var2[]
break;
  Case "Medium":
//Append to TextBox3
//Or add to var3[]
break;
}

EDIT: Sort into txtbox's or var[]'s, does this go-round make more sense?