查询多个项目的列表

本文介绍了查询多个项目的列表的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有以下内容：

public class DeviceListItem { public DeviceListItem（）; public string AssignedLot { get ; set ; } public string ID { get ; set ; } }

该列表可以包含 1.只有一项例如ID-001和Lot-AA 2.具有不同ID但常见批次的多个项目，例如带有LOT-AA的ID-001和带有LOT-AA的ID-002 3.具有不同ID和不同批次的多件物品，例如带有LOT-AA的ID-001和带有LOT-BB的ID-002 我也有以下函数返回一个字符串

private string generateErrorMessage（List< DeviceListItem> mixedDeviceList） { string error = string .Empty; // 如果只有1个设备 - 设备[< ID>]不属于此批次。它属于lot [< Lot>]。 if （mixedDeviceList.Count == 1 ） error = Device + mixedDeviceList [ 0 ]。ID + 不属于此批次。它属于批次 + mixedDeviceList [ 0 ]。AssignedLot; // 多个，同一批次 - 来自批次的< n>设备[ < Lot>]与当前批次混合。 // 多个，多个 - 有多个批次中的&n;设备与当前批次混合在一起。 return 错误; }

我需要查询列表并为上面标注的代码构建相应的字符串。 任何解决方案？ 我的尝试： 尝试使用Linq做一些事但没有成功

解决方案

使用LINQ很容易：

if （mixedDeviceList.Count == 1 ） { return string .Format（ 设备{0}不属于此批次。它属于批次{1}。，mixedDeviceList [ 0 ]。ID，mixedDeviceList [ 0 ]。AssignedLot）; } string firstLot = mixedDeviceList [ 0 ]。AssignedLot ; bool multipleLots = mixedDeviceList.Skip（ 1 ）。任意（d = > d.AssignedLot！= firstLot）; if （multipleLots） { return string .Format（ 有{0}个设备来自与当前批次混合的多个批次。，mixedDeviceList.Count）; } return string .Format（ 批次[{1}]中有{0}个设备与当前批次混合。，mixedDeviceList.Count， firstLot）;

或者，如果您更愿意避免使用LINQ：

if （mixedDeviceList.Count == 1 ） { return string .Format（ Device {0}不属于这个批次。它属于批次{1}。，mixedDeviceList [ 0 ]。ID，mixedDeviceList [ 0 ] AssignedLot）。 } string firstLot = mixedDeviceList [ 0 ]。AssignedLot ; bool multipleLots = false ; for （ int index = 1 ; index < mixedDeviceList.Count; index ++） { if （mixedDeviceList [index] .AssignedLot！= firstLot） { multipleLots = true ; break ; } } 如果（multipleLots） { return string .Format（ 有多个批次中的{0}个设备与当前批次混合。，mixedDeviceList.Count）; } return string .Format（ 批次[{1}]中有{0}个设备与当前批次混合。，mixedDeviceList.Count， firstLot）;

I have the following:

public class DeviceListItem { public DeviceListItem(); public string AssignedLot { get; set; } public string ID { get; set; } }

The list can contain 1. Only one item such as ID-001 and Lot-AA 2. Multiple items with different ID's but common Lots, such as ID-001 with LOT-AA and ID-002 with LOT-AA 3. Multiple items with different ID's and different Lots, such as ID-001 with LOT-AA and ID-002 with LOT-BB I also have the following function that returns a string

private string generateErrorMessage(List<DeviceListItem> mixedDeviceList) { string error = string.Empty; // If only 1 device - "Device [<ID>] does not belong to this lot. It belongs to lot [<Lot>]." if (mixedDeviceList.Count == 1) error = "Device" + mixedDeviceList[0].ID + " does not belong to this lot. It belongs to lot " + mixedDeviceList[0].AssignedLot; // Multiple, same Lot - "There are <n> devices from lot [<Lot>] mixed with the current lot." // Multiple, multiple - "There are <n> devices from multiple lots mixed with the current lot." return error; }

I need to query the list and build the appropriate string to be returned for the remarked code above. Any solutions ? What I have tried: Tried to do something using Linq but no sucess

解决方案

Easy to do with LINQ:

if (mixedDeviceList.Count == 1) { return string.Format("Device {0} does not belong to this lot. It belongs to lot {1}.", mixedDeviceList[0].ID, mixedDeviceList[0].AssignedLot); } string firstLot = mixedDeviceList[0].AssignedLot; bool multipleLots = mixedDeviceList.Skip(1).Any(d => d.AssignedLot != firstLot); if (multipleLots) { return string.Format("There are {0} devices from multiple lots mixed with the current lot.", mixedDeviceList.Count); } return string.Format("There are {0} devices from lot [{1}] mixed with the current lot.", mixedDeviceList.Count, firstLot);

Or, if you'd prefer to avoid LINQ:

if (mixedDeviceList.Count == 1) { return string.Format("Device {0} does not belong to this lot. It belongs to lot {1}.", mixedDeviceList[0].ID, mixedDeviceList[0].AssignedLot); } string firstLot = mixedDeviceList[0].AssignedLot; bool multipleLots = false; for (int index = 1; index < mixedDeviceList.Count; index++) { if (mixedDeviceList[index].AssignedLot != firstLot) { multipleLots = true; break; } } if (multipleLots) { return string.Format("There are {0} devices from multiple lots mixed with the current lot.", mixedDeviceList.Count); } return string.Format("There are {0} devices from lot [{1}] mixed with the current lot.", mixedDeviceList.Count, firstLot);