改变Datatable的某列数据类型

//这里的dt是原datatable，dtNew是创建的datatable
DataTable dtNew = dt.Clone();
dtNew.Clear();
//把到货状态这一列设置为string类型
dtNew.Columns["到货状态"].DataType = System.Type.GetType("System.String");
//按行导入值，把dt中的值导入到dtNew中
for (int i = 0; i < dt.Rows.Count; i++)
{
    dtNew.ImportRow(dt.Rows[i]);
}

for (int i = 0; i < dtNew.Rows.Count; i++)
{
    for (int j = 0; j < dtNew.Columns.Count; j++)
    {
        if (dtNew.Columns[j].ColumnName == "到货状态")
        {
            dtNew.Rows[i][j] = dtNew.Rows[i][j].ToString() switch
            {
                    "1" => "未到货",
                    "2" => "部分到货",
                    "3" => "全部到货",
                    _ => dtNew.Rows[i][j],
            };
        }
    }
}