C# 如何将一个数据表附加到另一个数据表
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How to append one DataTable to another DataTable
提问by Jason Kanaris
I would like to append one DataTable to another DataTable. I see the DataTable class has two methods; "Load(IDataReader)" and "Merge(DataTable)". From the documentation, both appear to 'merge' the incoming data with the existing DataTable if rows exist. I will be doing the merge in a data access layer.
我想将一个 DataTable 附加到另一个 DataTable。我看到 DataTable 类有两个方法；“加载（IDataReader）”和“合并（数据表）”。从文档中，如果存在行，两者似乎都将传入数据与现有数据表“合并”。我将在数据访问层中进行合并。
I could could usa an IDataReader and use the Load method to merge the DataTables. Or I could load a DataSet using the IDataReader, get the DataTable from the DataSet, and then use the Merge method to merge the DataTables.
我可以使用 IDataReader 并使用 Load 方法来合并数据表。或者我可以使用 IDataReader 加载数据集，从数据集中获取数据表，然后使用 Merge 方法合并数据表。
I was wondering if someone could tell me which is the proper method to use?
我想知道是否有人可以告诉我使用哪种方法是正确的？
Alternatively, let me know if you have a different suggestion on how to accomplish this task.
或者，如果您对如何完成此任务有不同的建议，请告诉我。
采纳答案by Thies
Merge takes a DataTable, Load requires an IDataReader - so depending on what your data layer gives you access to, use the required method. My understanding is that Load will internally call Merge, but not 100% sure about that.
Merge 需要一个 DataTable，Load 需要一个 IDataReader - 因此根据您的数据层允许您访问的内容，使用所需的方法。我的理解是 Load 会在内部调用 Merge，但不能 100% 确定。
If you have two DataTables, use Merge.
如果您有两个数据表，请使用合并。
回答by Sam Axe
You could let your DataAdapterdo the work. DataAdapter.Fill(DataTable)will append your new rows to any existing rows in DataTable.
你可以让你DataAdapter的工作。 DataAdapter.Fill(DataTable)将您的新行附加到DataTable.
回答by Xtian11
The datatype in the same columns name must be equals.
相同列名中的数据类型必须相等。
dataTable1.Merge(dataTable2);
After that the result is:
之后的结果是：
dataTable1 = dataTable1 + dataTable2
数据表1 = 数据表1 + 数据表2
回答by Ramesh Venkataswamy
Add two datasets containing datatables, now it will merge as required
添加两个包含数据表的数据集，现在它会根据需要合并
DataSet ds1 = new DataSet();
DataSet ds2 = new DataSet();
DataTable dt1 = new DataTable();
dt1.Columns.Add(new DataColumn("Column1", typeof(System.String)));
DataRow newSelRow1 = dt1.NewRow();
newSelRow1["Column1"] = "Select";
dt1.Rows.Add(newSelRow1);
DataTable dt2 = new DataTable();
dt2.Columns.Add(new DataColumn("Column1", typeof(System.String)));
DataRow newSelRow2 = dt1.NewRow();
newSelRow2["Column1"] = "DataRow1Data"; // Data
dt2.Rows.Add(newSelRow2);
ds1.Tables.Add(dt1);
ds2.Tables.Add(dt2);
ds1.Tables[0].Merge(ds2.Tables[0]);
Now ds1 will have the merged data
现在 ds1 将有合并的数据
回答by Waheed Alzekry
use loop
使用循环
for (int i = 0; i < dt1.Rows.Count; i++)
{
dt2.Rows.Add(dt1.Rows[i][0], dt1.Rows[i][1], ...);//you have to insert all Columns...
}
回答by Derpy
Consider a solution that will neatly handle arbitrarily many tables.
考虑一个可以巧妙处理任意多个表的解决方案。
//ASSUMPTION: All tables must have the same columns
var tables = new List<DataTable>();
tables.Add(oneTableToRuleThemAll);
tables.Add(oneTableToFindThem);
tables.Add(oneTableToBringThemAll);
tables.Add(andInTheDarknessBindThem);
//Or in the real world, you might be getting a collection of tables from some abstracted data source.
//behold, a table too great and terrible to imagine
var theOneTable = tables.SelectMany(dt => dt.AsEnumerable()).CopyToDataTable();
Encapsulated into a helper for future reuse:
封装成一个 helper 以备将来重用：
public static DataTable CombineDataTables(params DataTable[] args)
{
return args.SelectMany(dt => dt.AsEnumerable()).CopyToDataTable();
}
Just have a few tables declared in code?
只是在代码中声明了几个表？
var combined = CombineDataTables(dt1,dt2,dt3);
Want to combine into one of the existing tables instead of creating a new one?
想要合并到现有表之一而不是创建新表吗？
dt1 = CombineDataTables(dt1,dt2,dt3);
Already have a collection of tables, instead of declared one by one?
已经有一个表的集合，而不是一个一个地声明？
//Pretend variable tables already exists
var tables = new[] { dt1, dt2, dt3 };
var combined = CombineDataTables(tables);
