将数据表数组中的数据列与数据合并 [英] Merging datacolumns from a datatable array with data

问题描述

我有一个数据表数组，



DataSet ds = //我从数据源收集数据



我从ds.Tables初始化 DataTable []



DataTable [] tableArray = ds.Tables.Cast< DataTable>（）;



这些表格都有一行数据



现在是我可以做的另一种方法，合并这些DataTables的列并放置数据在列中根据需要？



示例数据



让我的 DataSet ds 有2个表 dtA 和 dtB



输入



dtA



Col1 A

Col2 B



dtB



Col3 C

Col4 D



输出



dtMerged



Col1 A

Col2 B

Col3 C

Col4 D



我尝试了什么：



我在列和行上运行了一个简单的 foreach 循环形成一个更大的数据表。

此外，

I have a datatable array,

DataSet ds = // I gather data from a datasource

I initialize a DataTable[] from ds.Tables

DataTable[] tableArray = ds.Tables.Cast<DataTable>();

These tables all have a single row of data

Now is an alternate approach to what I have done possible, to merge the columns of these DataTables and also put data in the columns as required ?

Example Data

Let my DataSet ds have 2 tables dtA and dtB

Input

dtA

Col1 A
Col2 B

dtB

Col3 C
Col4 D

Output

dtMerged

Col1 A
Col2 B
Col3 C
Col4 D

What I have tried:

I have run a simple foreach loop on the columns and the rows to form a bigger datatable.
Also,

DataTable bigTable = new DataTable();
Enumerable.Range(0, ds.Tables.Count).ToList().ForEach(i => bigTable.Merge(ds.Tables[i]));

DataTable bigTable2 = bigTable.Clone();
DataRow[] rowCollection = bigTable.Rows.Cast<DataRow>().ToArray();
DataRow newDR = bigTable2.NewRow();
Enumerable.Range(0, bigTable.Columns.Count).ToList().ForEach(j =>
{
    newDR[bigTable.Columns[j].ColumnName] = rowCollection.Select(dr => dr[j].ToString()).Last(s => !string.IsNullOrWhiteSpace(s));
});

注意：我有理由不执行复杂的单个查询并获取单个数据表。

Note: I have reasons not to execute a complex single query and fetch a single datatable.

推荐答案

嗯，一句话：合并英文可能意味着：连接，链接，加入，合并，混合，团结...



如果我理解你，你想合并数据，什么在编程语言中众所周知为加入 [< a href =https://docs.microsoft.com/en-us/dotnet/articles/csharp/language-reference/keywords/join-clause\"target =_ blanktitle =New Window> ^ ]

Well, a word: "merge" in English may mean: connect, link, join, merge, mix, unite...

If i understand you well, you want to merge data, what is well known in programming language as join[^]

var mergedData = from a in tableA.AsEnumerable()
        join b in tableB.AsEnumerable() on a.Field<int>("Key") equals b.Field<int>("ForeignKey")
        select new
       {
           A = a.Field<int>("Key"),
           B = a.Field<string>("FieldB"),
           C = b.Field<int>("ForeignKey"),
           D = b.Field<string>("FieldD")
       };

DataTable bigTable = new DataTable();
bigTable.Columns.AddRange(new DataColumn[]
	{
		new DataColumn("Key", typeof(int)),
		new DataColumn("FieldB", typeof(string)),
		new DataColumn("ForeignKey", typeof(int))
		new DataColumn("FieldD", typeof(string))
	});
bigTable = mergedData.CopyToDataTable();

欲了解更多详情，请参阅：

加入运算符（LINQ to DataSet） [ ^ ]

LINQ to DataSet中的查询 [ ^ ]

从查询创建DataTable（LINQ to DataSet） [ ^ ]

---

如果你想合并具有相同结构的表，试试这个：

For further details, please see:
Join Operators (LINQ to DataSet)[^]
Queries in LINQ to DataSet[^]
Creating a DataTable From a Query (LINQ to DataSet)[^]

---

In case you want to merge tables, which have the same structure, try this:

//create "merged table" with destination structure
DataTable bigTable = new DataTable();
//all tables have to have the same structure!
bigTable.Columns.AddRange(new DataColumn[]
    {
        new DataColumn("EmpId", typeof(int)),
        new DataColumn("EmployeeName", typeof(string)),
        new DataColumn("DepartmentId", typeof(int))
    });
    //copy data into destination table ("merged table")
foreach(DataTable t in ds.Tables)
{
    foreach(DataRow r in t.Rows)
    {
        bigTable.ImportRow(r);
    }
}

祝你好运！

Good luck!

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