将dataGridView数据转成DataTable

如已绑定过数据源：

DataTable dt = (dataGridView1.DataSource as DataTable)

如未绑定过数据源：

public DataTable GetDgvToTable(DataGridView dgv)
{
DataTable dt = new DataTable();

// 列强制转换
for (int count = 0; count < dgv.Columns.Count; count++)
{
DataColumn dc = new DataColumn(dgv.Columns[count].Name.ToString());
dt.Columns.Add(dc);
}

// 循环行
for (int count = 0; count < dgv.Rows.Count; count++)
{
DataRow dr = dt.NewRow();
for (int countsub = 0; countsub < dgv.Columns.Count; countsub++)
{
dr[countsub] = Convert.ToString(dgv.Rows[count].Cells[countsub].Value);
}
dt.Rows.Add(dr);
}
return dt;
}

from: http://www.cnblogs.com/linji/archive/2012/10/11/2719471.html