//单元格点击事件
        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            //获取某个单元格的值的数据类型名称
            MessageBox.Show(dataGridView1[e.ColumnIndex, e.RowIndex].Value.GetType().Name);
        }

------解决方案--------------------
for循环选中列

------解决方案--------------------
C# code

 foreach (DataGridViewTextBoxCell cell in dataGridView1.SelectedCells)
            {
                string typename = cell.Value.GetType().Name;
            }

------解决方案--------------------

楼上是对的，稍微修改一下
C# code

private void button1_Click(object sender, EventArgs e)
        {
            List<string> list = new List<string>();
            foreach (DataGridViewCell cell in dataGridView1.SelectedCells)
            {
                list.Add("[" + cell.OwningColumn.Name + "]" + "的数据类型为:" + cell.Value.GetType().Name);
            }
            foreach (string s in list.Distinct<string>())
                MessageBox.Show(s);
        }

------解决方案--------------------
C# code
using System.Linq;