DataTable in C#
Let's say I have two DataTables DT1 and DT2 with a single row.
DT1 has 3 columns: Col1, 开发者_运维技巧Col2, and Col3
and
DT2 has 2 columns: ColA, ColB.
Is it possible to join these two DataTables horizontally so I get Col1, Col2, Col3, ColA, and ColB?
I thin you have to add new columns and copy data either in third table or in one of the existing table
DataTable dt1 = new DataTable();
dt1.Columns.Add("col1", typeof(string));
dt1.Columns.Add("col2", typeof(string));
dt1.Columns.Add("col3", typeof(string));
DataTable dt2 = new DataTable();
dt2.Columns.Add("cola", typeof(string));
dt2.Columns.Add("colb", typeof(string));
object[] row = {'1', '2', '3'};
dt1.Rows.Add(row);
object[] row1 = { 'a', 'b' };
dt2.Rows.Add(row1);
// Create columns in dt1
dt1.Columns.Add("cola", typeof(string));
dt1.Columns.Add("colb", typeof(string));
// Copy data from dt2
dt1.Rows[0]["cola"] = dt2.Rows[0]["cola"];
dt1.Rows[0]["colb"] = dt2.Rows[0]["colb"];
So long as you simply want a collection you can bind to you can do the following:
var results = from rs1 in table1.Rows.Cast<DataRow>()
join rs2 in table2.Rows.Cast<DataRow>() on rs1.Field<int>("col1") equals rs2.Field<int>("colA")
select new { col1 = rs1.Field<int>("col1"), col2 = rs1.Field<string>("col3"), col3 = rs1.Field<string>("col3"), colA = rs1.Field<int>("colA"), colB = rs1.Field<string>("colB") };
You would not get a DataTable
but an IEnumerable<T>
collection of anonymous type objects as defined in the select statement. Obvoiusly i have just guessed the join criteria and the data type of the columns so you would have to specify those as appropriate for your actual data.
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