how sort datgridview or listview like windows explorer

Le rner

hi all, i have a datagrid and listview with some items. like,counting from 1 to 20 than when i sort its shows 1,10,11 and so on i want it sort like 1,2,3 as acending or descending selected plz help me for this. thanks in advance.

OriginalGriff

That's the correct sorting, for your data - the problem is deeper than that and probably requires changes elsewhere. When you sort numbers, you expect this order: 1, 2, 3, ... 9, 10, 11, ... 19, 20 ... But when you sort strings, the whole comparison is based on the first different pair of characters you encounter in the two strings. So if you compare "APPLE" with "APART"it does this: 1) Compare index [0]: 'A' and 'A'. Same. Continue 2) Compare index [1]: 'P' and 'P'. Same. Continue 3) Compare index [2]: 'P' and 'A'. Different: Since 'A' is less than 'P' return the second string as the "lowest" value. Indexes [3] and above aren't even looked at. That's all fine and dandy, except if you are comparing string values and expecting numeric ordering, because the string ordering is used regardless of the string content and the order goes: 1, 10, 11, ... 19, 2, 20, 21, ... 29, 3, 30, ... This problem gets even worse with date based string data! So what you actually need to do is look to the source of your data and find out why it is a string rather than a numeric value, and correct that. Often, it's due to bad design in a DB where all the data is stored as strings because that was easy to do and caused no errors when bad numbers or bad dates where INSERTed - but the best way to fix this is to fix the DB design so you store numbers in numeric fields, and dates in date based fields.

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Richard Deeming

If your data contains a mixture of numbers and strings and you want to precisely match the way Windows Explorer sorts file names, then you can either P/Invoke the StrCmpLogicalW function, or use a managed implementation: Numeric String Sort in C#[^]

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Le rner

yes i want to compare string items

Dave Kreskowiak

If you're trying to sort numeric items as strings, you're not going to get the result you want. The column that you want to sort in 1, 2, 3, ... order MUST be numeric in order for sorting to work the way you want.

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Dave Kreskowiak

Le rner

thanks this really helps me...

RobertSF

One solution is to create a class for a "sortable" list and use that as your data source in the DGV. I found this somewhere and have been using it with success. Thanks to the unsung hero who wrote it.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.InteropServices;

namespace YourNamespace
{
internal static class NativeMethods
{
[DllImport("shlwapi.dll", CharSet = CharSet.Unicode)]
internal static extern int StrCmpLogicalW(string aString, string bString);
}

internal class SortableList : BindingList
{
    protected override bool SupportsSortingCore
    {
        get
        {
            return true;
        }
    }

    protected override void ApplySortCore(PropertyDescriptor prop, ListSortDirection direction)
    {
        int modifier = direction == ListSortDirection.Ascending ? 1 : -1;
        if (prop?.PropertyType.GetInterface("IComparable") != null)
        {
            var items = Items.ToList() as List;
            items.Sort(new Comparison((a, b) =>
            {
                var aVal = prop.GetValue(a).ToString() as string;
                var bVal = prop.GetValue(b).ToString() as string;
                return NativeMethods.StrCmpLogicalW(aVal, bVal) \* modifier;
            }));
            Items.Clear();
            foreach (var i in items) Items.Add(i);
        }
    }
}

}

Le rner

for string its working fine, now what about date time, how i compare here date time of file, to sort according this

Richard Deeming

Don't use a string column; use a DateTime column, and apply the format in the UI. If you really want to sort dates stored as strings, then you have to store them in a sortable format - eg: yyyy-MM-dd HH:mm:ss.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer