Question

setlocal enabledelayedexpansion仅适用于批处理文件吗？如何在cmd提示符中使用setlocal enabledelayedexpansion？

Answer 1

您可以使用命令OleDbCommand cmd = new OleDbCommand("SELECT Table1.Cd_AtributosNormais as Cd_AtributosNormais, Table2.Nm_Atr as Nm_Atr FROM Table1 Left outer join Table2 on Table1.Cd_AtributosNormais = Table2.Cd_AtributosNormais", cn); OleDbDataReader reader = cmd.ExecuteReader(); DataTable table = new DataTable(); table.Load(reader); DataRow row = table.NewRow(); row["Nm_Atr"] = ""; table.Rows.InsertAt(row, 0); this.btCmbAtkBaAtr1.DataContext = table.DefaultView; this.btCmbAtkBaAtr1.DisplayMemberPath = "Nm_Atr"; this.btCmbAtkBaAtr1.SelectedValuePath = "Cd_AtributosNormais"; cmd.ExecuteNonQuery(); reader.Close(); reader.Dispose(); } catch(Exception ex) { MessageBox.Show(ex.Message); } finally { cn.Close(); cn.Dispose(); }

在命令提示符中启用延迟扩展

来自cmd /V:ON：

cmd /?

Answer 2

从我的CMD窗口中了解示例：Copy&Paste：

==>echo !os! %pp%
!os! %pp%

==>cmd /E:ON /V:ON /K set "pp=yy" & set pp & echo !os! !pp!

==>echo !os! %pp%
Windows_NT yy

==>exit
Environment variable pp  not defined
!os! !pp!

==>cmd /E:ON /V:ON /K set "pp=yy" ^& set pp ^& echo !os! !pp!
pp=yy
Windows_NT yy

==>echo !os! %pp%
Windows_NT yy

==>exit

==>echo !os! %pp%
!os! %pp%

==>

说明：

echo !os! %pp%返回!os! %pp%，显示已停用的延迟扩展和当前CLI中未定义的pp变量;
cmd /E:ON /V:ON /K set "pp=yy" & set pp & echo !os! !pp!什么都不返回，Windows命令解释器的新实例已启用延迟扩展（请参阅echo !os! %pp%输出）;
exit在父CLI实例中返回set pp & echo !os! !pp!的结果：Environment variable pp not defined和!os! !pp!;
cmd /E:ON /V:ON /K set "pp=yy" ^& set pp ^& echo !os! !pp!在新的CLI实例中返回pp=yy和Windows_NT yy（请注意&转义的所有^};
echo !os! %pp%在新的CLI实例中返回Windows_NT yy（它会在子项中显示延迟扩展已启用和pp变量已定义 CLI）;
exit到父CLI实例;
echo !os! %pp%再次返回!os! %pp%。

在cmd提示符中使用“setlocal enabledelayedexpansion”

2 个答案: