Question

在我的C#代码中,我有两个数据表:

inventory_table

SKU	Title	Qty
SAM-GAL-S7-32	Samsung Galaxy S7 128GB	5
SAM-GAL-S6-64	Samsung Galaxy S6 64GB	10
IP-13P-128	Apple iPhone 13 Pro 128GB	9
IP-12-64	Apple iPhone 12 64GB	6
LG-V60-128	LG V60 128GB	3

页: 1

SKU	Qty
SAM-GAL-S6-64	2
IP-13P-128	1
LG-V60-128	1

I want to substract the quantity of 页: 1 from the inventory_table for the matching SKU, so the result should be:

inventory_table (updated)

SKU	Qty
SAM-GAL-S7-32	5
SAM-GAL-S6-64	8
IP-13P-128	8
IP-12-64	6
LG-V60-128	2

The rows with SKU "SAM-GAL-S6-64", "IP-13P-128" and "LG-V60-128" now have updated quantity. These tables only exists in memory, not in database, and the result table will be exported to a text file. In reality, inventory_table would have a few thousand rows while 页: 1 has 20-30 rows. I believe this task can be done with LINQ. Please advise. Thanks

无。我需要咨询

Answer 1

• 检查以下编码:

using System;
using System.Data;
using System.Linq;

class Program
{
    static void Main()
    {
        // Create sample DataTables
        DataTable inventoryTable = new DataTable();
        inventoryTable.Columns.Add("SKU", typeof(string));
        inventoryTable.Columns.Add("Qty", typeof(int));
        
        DataTable orderTable = new DataTable();
        orderTable.Columns.Add("SKU", typeof(string));
        orderTable.Columns.Add("Qty", typeof(int));
        
        // Populate sample data (replace with your data)
        inventoryTable.Rows.Add("SAM-GAL-S7-32", 5);
        inventoryTable.Rows.Add("SAM-GAL-S6-64", 10);
        inventoryTable.Rows.Add("IP-13P-128", 9);
        inventoryTable.Rows.Add("IP-12-64", 6);
        inventoryTable.Rows.Add("LG-V60-128", 3);
        
        orderTable.Rows.Add("SAM-GAL-S6-64", 2);
        orderTable.Rows.Add("IP-13P-128", 1);
        orderTable.Rows.Add("LG-V60-128", 1);

        // Subtract quantities using LINQ
        var result = from inventoryRow in inventoryTable.AsEnumerable()
                     join orderRow in orderTable.AsEnumerable()
                     on inventoryRow.Field<string>("SKU") equals orderRow.Field<string>("SKU")
                     select new
                     {
                         SKU = inventoryRow.Field<string>("SKU"),
                         Qty = inventoryRow.Field<int>("Qty") - orderRow.Field<int>("Qty")
                     };

        // Update the inventoryTable with the new quantities
        foreach (var item in result)
        {
            DataRow row = inventoryTable.AsEnumerable()
                                        .Where(r => r.Field<string>("SKU") == item.SKU)
                                        .FirstOrDefault();
            if (row != null)
            {
                row.SetField("Qty", item.Qty);
            }
        }

        // Display the updated inventoryTable
        Console.WriteLine("Updated inventory_table:");
        foreach (DataRow row in inventoryTable.Rows)
        {
            Console.WriteLine($"{row["SKU"]}	{row["Qty"]}");
        }
    }
}

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