正在做一数据分析软件,遇到关于DataGridView的行列转置的问题(附代码):

以下的解决方案不太理想,主要是效率问题.遇到超过300行的表转置过来速度就牛慢.
而令我感到奇怪的是,同样的方法,在程序启动时调用速度却很快.而运行过程中,再点工具栏按钮进行转置却很慢.                //横向显示表格
       private void RotateDGV(DataTable dt , DataGridView DgvData)
      {
                DgvData.Rows.Clear();
                DgvData.Columns.Clear();
                
                //添加列到DgvData
                  DataGridViewTextBoxColumn column = new DataGridViewTextBoxColumn();
                column.HeaderText = column.Name = dt.Columns[0].ColumnName;
                column.FillWeight = 10;
                DgvData.Columns.Add(column);
                DataGridViewTextBoxColumn[] columns = new DataGridViewTextBoxColumn[dt.Rows.Count];
                for (int dtrow = 0; dtrow < dt.Rows.Count; dtrow++)
                {
                    column = new DataGridViewTextBoxColumn();
                    object o = dt.Rows[dtrow][0];
                    if (o.GetType().Name == "DateTime")
                    {
                        column.HeaderText = column.Name = ((DateTime)o).ToString("yyyy-MM");
                    }
                    else
                        column.HeaderText = o.ToString();                    columns[dtrow] = column;
                    column.FillWeight = 10;
                }
                DgvData.Columns.AddRange(columns); ///在运行中强行中断, 光标总是停留在这一行.                //添加数据
                  DgvData.Rows.Add(dt.Columns.Count - 1);
                for (int dtcol = 1; dtcol < dt.Columns.Count; dtcol++)
                {
                    DgvData[0, dtcol - 1].Value = dt.Columns[dtcol].ColumnName;
                    string colType = DgvData[0, dtcol - 1].Value.GetType().Name;
                    DgvData[0, dtcol - 1].Style.Alignment = colType
                        == "String" ? DataGridViewContentAlignment.MiddleLeft : DataGridViewContentAlignment.MiddleCenter;
                    for (int dtrow = 0; dtrow < dt.Rows.Count; dtrow++)
                    {
                        DgvData[dtrow + 1, dtcol - 1].Value = dt.Rows[dtrow][dtcol];
                    }
                }
        }