How to sort data in gridview?

Question

I am trying to sort the data in gridview

everything is working fine but numeric column(Marks) taking sorting for 1st number only

Code:

 protected void gvTrHty_Sorting(object sender, GridViewSortEventArgs e)
    {
        try
        {
            this.gviewSorting(e.SortExpression);
        }
        catch (Exception ex)
        {
            string arg_15_0 = ex.Message;
        }
    }

 private void gviewSorting(string strSortExp)
    {
        if (this.ViewState["dvTrain"] == null)
        {
            DataSet dataSet = this.BindTraining();
            dv = dataSet.Tables[0].DefaultView;
        }
        else
        {
            DataSet dataSet2 = (DataSet)this.ViewState["dvTrain"];
            TrainingHistory.dv = dataSet2.Tables[0].DefaultView;
        }
        if (TrainingHistory.sortorder)
        {
            TrainingHistory.sortorder = false;
            TrainingHistory.dv.Sort = strSortExp + " DESC";
        }
        else
        {
            TrainingHistory.sortorder = true;
            TrainingHistory.dv.Sort = strSortExp;
        }
        this.BindData(TrainingHistory.dv);
    }

If I have values in Mark(column) in gridview

   Marks----> When I click this for sorting it's taking     Marks     

    1                                                         1                            
    8                         1st number only sorted  --->    12
    40                                                        21 
    12                                                        40
    21                                                        8

It's doing alphabetical sort, instead of numerical. Is the Marks column being converted to text somewhere? — freefaller
Do you use binding list as a data source? If not, are you able to? — Dino Velić

Karl Anderson Karl Anderson · Accepted Answer · 2013-11-11T13:52:00

It is treating your "numerical" data as a string and doing the sort against this string value, thus "40" is less than "8".

Your options are:

Put leading zeroes on the numeric field values, which is probably a no-go for obvious reasons, this would allow the existing sort to work correctly. I suppose you could temporarily put leading zeroes and then rip them out after the sort, but this sounds like a headache.

Implement your own sorting logic, like this:

public sealed class GenericComparer<T> : IComparer<T>
{
    public enum SortOrder
    {
        Ascending = 0,
        Descending = 1
    }

    private string sortColumn;
    private SortOrder sortingOrder;

    public string SortColumn
    {
        get
        {
            return this.sortColumn;
        }
    }

    public SortOrder SortingOrder
    {
        get
        {
            return this.sortingOrder;
        }
    }

    public GenericComparer(string theSortColumn, SortOrder theSortingOrder)
    {
        this.sortColumn = theSortColumn;
        this.sortingOrder = theSortingOrder;
    }

    public int Compare(T x, T y)
    {
        PropertyInfo thePropertyInfo = typeof(T).GetProperty(this.sortColumn);
        IComparable object1 = (IComparable)thePropertyInfo.GetValue(x, null);
        IComparable object2 = (IComparable)thePropertyInfo.GetValue(y, null);

        if (this.sortingOrder == SortOrder.Ascending)
        {
            return object1.CompareTo(object2);
        }
        else
        {
            return object2.CompareTo(object1);
        }
    }
}

Now in your call to .Sort() method, you pass a new instance of this helper class (passing it the column you want to sort by and the direction you want to sort - ascending or descending).

Since the comparer logic above uses generics, you can pass whatever type you want to sort by (i.e. int, DateTime, or even entire domain objects).

How to sort data in gridview?

1 Answers