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 

Answer 1

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:

1. 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.

2. 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 (ie int , DateTime , or even entire domain objects).