C#网络应用编程一个转换方式错误！！！求高手解答~

部分代码：
public Form1()
        {
            InitializeComponent();
            dataGridView1.AllowUserToAddRows = false;
            dataGridView1.AutoResizeColumns();
            dataGridView1.AutoSizeColumnsMode =DataGridViewAutoSizeColumnMode.AllCells;
            dataGridView1.MultiSelect = false;
        }
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出现错误！！！

错误 1 无法将类型“System.Windows.Forms.DataGridViewAutoSizeColumnMode”隐式转换为“System.Windows.Forms.DataGridViewAutoSizeColumnsMode”。存在一个显式转换(是否缺少强制转换?) c:\users\liu\documents\visual studio 2010\Projects\ProcessMonitor\ProcessMonitor\Form1.cs 21 48 ProcessMonitor
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求高手解答啊  越快越好！！！ --------------------编程问答-------------------- DataGridViewAutoSizeColumnMode

改成

DataGridViewAutoSizeColumnsMode --------------------编程问答-------------------- dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells; --------------------编程问答-------------------- 谢谢楼上的大虾就是此处的原因 --------------------编程问答-------------------- 大虾还有一个问题
foreach (Process p in myProcess)
            {


                int newRowIndex = dataGridView1.Rows.Add();
                DataGridViewRow row=dataGridView1.Rows[newRowIndex];
                row.Cells[0].Value = p.Id;
                row.Cells[1].Value = p.ProcessName;
                row.Cells[2].Value = string.Format("{0:###,##0.00}MB", p.WorkingSet64 / 1024.0f / 1024.0f);
                try
                {
                    row.Cells[3].Value = string.Format("{0}", p.StartTime);
                    row.Cells[4].Value = p.MainModule.FileName;
                }
                catch {
                    row.Cells[3].Value = "";
                    row.Cells[4].Value = "";
                }

            }

DataGridView 控件添加行。必须首先添加列。
--------------------------------怎样添加列丫？？初学神马都不懂求大虾解答

补充：.NET技术 ,  C#