类似这应该起作用：

var list = myDataGridView.Rows.OfType<DataGridViewRow>()
           .Select(x => x.Cells["MYCOLUMN"].Value.ToString());
var q = from x in list
    group x by x into g
    let count = g.Count()
    orderby count descending
    select new { Value = g.Key, Count = count };

其中 MYCOLUMN 是

EDIT：

此代码返回包含重复项的行列表的项目列表：

this code returns a list of items that contains also the list of rows with the duplications:

var q = myDataGridView.Rows.OfType<DataGridViewRow>()
        .GroupBy(x => x.Cells["MYCOLUMN"].Value.ToString())
        .Select(g => new {Value=g.Key, Count=g.Count(), Rows=g.ToList()})
        .OrderByDescending(x => x.Count);

因此，如果您有5行，例如：

so if you have 5 rows e.g. :

ID     MYCOLUMN
 0         A
 1         B
 2         C
 3         A
 4         B   

q 将包含3个元素：

 Key="A", Count=2, Rows={ [0 - A] [3 - A]}
 Key="B", Count=2, Rows={ [1 - B] [4 - B]}
 Key="C", Count=1, Rows={ [2 - C] }