两个datatble合并成一个

Question

dt1 字段 a ，b，c，d，e     dt2字段 m，n，p如果d=m and e=n 那么p就作为dt1的一个字段p 组后要的dt3就是  a,b,c,d,e,p

Answer 1

for循环加if判断不难啊就是写两个datatable麻烦

Answer 2

这个可以  不知道浅拷贝行不  你试下clone();

Answer 3

这个可以  不知道浅拷贝行不  你试下clone();

Answer 4

有一个叫DataRelation的，　楼主试试.附代码示例：
#region Using directivesusing System;
using System.Data;            // Use ADO.NET namespace
using System.Data.SqlClient;  // Use SQL Server data provider namespace
using System.Collections.Generic;
using System.Text;#endregionnamespace ManyRelations
{
class Program
{
static void Main(string[] args)
{
// Specify SQL Server-specific connection string SqlConnection thisConnection = new SqlConnection(@"Data Source=HUI\SQLSERVER;Initial Catalog=Northwind;Integrated Security=True"); DataSet thisDataSet = new DataSet();
SqlDataAdapter custAdapter = new SqlDataAdapter("SELECT * FROM Customers", thisConnection);
custAdapter.Fill(thisDataSet, "Customers"); SqlDataAdapter orderAdapter = new SqlDataAdapter("SELECT * FROM Orders", thisConnection);
orderAdapter.Fill(thisDataSet, "Orders"); SqlDataAdapter detailAdapter = new SqlDataAdapter("SELECT * FROM [Order Details]", thisConnection);
detailAdapter.Fill(thisDataSet, "Order Details"); SqlDataAdapter prodAdapter = new SqlDataAdapter("SELECT * FROM Products", thisConnection);
prodAdapter.Fill(thisDataSet, "Products");            //创建DataRelation对象
DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
thisDataSet.Tables["Customers"].Columns["CustomerID"],
thisDataSet.Tables["Orders"].Columns["CustomerID"]); DataRelation orderDetailRel = thisDataSet.Relations.Add("OrderDetail",
thisDataSet.Tables["Orders"].Columns["OrderID"],
thisDataSet.Tables["Order Details"].Columns["OrderID"]); DataRelation orderProductRel = thisDataSet.Relations.Add(
  "OrderProducts", thisDataSet.Tables["Products"].Columns["ProductID"],
               thisDataSet.Tables["Order Details"].Columns["ProductID"]);               //此处Products是父表 foreach (DataRow custRow in thisDataSet.Tables["Customers"].Rows)
{
Console.WriteLine("Customer ID: " + custRow["CustomerID"]); foreach (DataRow orderRow in custRow.GetChildRows(custOrderRel))        //提取子行
{
Console.WriteLine("\tOrder ID: " + orderRow["OrderID"]);
Console.WriteLine("\tOrder Date: " + orderRow["OrderDate"]); foreach (DataRow detailRow in
 orderRow.GetChildRows(orderDetailRel))
{
Console.WriteLine("\t\tProduct: " +
detailRow.GetParentRow(orderProductRel)["ProductName"]);        //从"多端"进入"一端",获取父对象
Console.WriteLine("\t\tQuantity: " + detailRow["Quantity"]);
}
}
}
thisConnection.Close();
Console.Write("Program finished, press Enter/Return to continue:");
Console.ReadLine();
}
}
}

Answer 5

这里我是按着你的需求，自己定义了一些数据            DataTable dt1, dt2, dt3;
            dt1 = new DataTable();
            dt2 = new DataTable();
            dt1.Columns.Add(new DataColumn("a"));
            dt1.Columns.Add(new DataColumn("b"));
            dt1.Columns.Add(new DataColumn("c"));
            dt1.Columns.Add(new DataColumn("d"));
            dt1.Columns.Add(new DataColumn("e"));
            dt2.Columns.Add(new DataColumn("m"));
            dt2.Columns.Add(new DataColumn("n"));
            dt2.Columns.Add(new DataColumn("p"));            dt3 = dt1.Clone();
            dt3.Columns.Add(new DataColumn("p"));            for (int i = 0; i < 10; i++)
            {
                DataRow row = dt1.NewRow();
                foreach (DataColumn col in dt1.Columns)
                {
                    row[col] = i.ToString();
                }
                dt1.Rows.Add(row);
            }            for (int i = 5; i < 10; i++)
            {
                DataRow row = dt2.NewRow();
                foreach (DataColumn col in dt2.Columns)
                {
                    row[col] = i;
                }
                dt2.Rows.Add(row);
            }
            foreach (DataRow row in dt1.Rows)
            {
                DataRow[] t = dt2.Select("m='" +row["d"]+"' and n='" + row["e"]+"'");//找到相同的行
                foreach (DataRow r in t)
                {
                    DataRow r3 = dt3.NewRow();
                    r3["a"] = row["a"];
                    r3["b"] = row["b"];
                    r3["c"] = row["c"];
                    r3["d"] = row["d"];
                    r3["e"] = row["e"];
                    r3["p"]=r["p"];
                    dt3.Rows.Add(r3);                }            }            foreach (DataRow r in dt3.Rows)
            {
                foreach (DataColumn c in dt3.Columns)
                {
                    Console.Write(r[c]);
                    Console.Write("...");
                }
                Console.WriteLine();
            }

Answer 6

datatable.merge
d,e两列设置为主键列