datable explanation, and usage

I. Datasets, DataTable, DataRow, DataColumn

1 "Adding a DataTable to a dataset

DATASET.TABLES.ADD (DataTable)

Instance:

DataSet ds=new DataSet ();

DataTable table=new DataTable ("Student Table");

Ds. Tables.add (table);
2 "Reading a DataTable from a dataset

Datatable=dataset.tables[0] or dataset.tables["table name"]

Instance:

DataTable Table=ds[i] or DataTable table=ds["Student Table"]

I is the index value in the dataset because the dataset can hold multiple DataTable, you can find a DataTable based on the index value, or write the name of the DataTable directly to find a DataTable
3 "Add row
DataTable t=new DataTable ();
DataRow R=t.newrow ();
r["column name"]= column value;
T.rows.add (R);

Instance:

DataTable: Student Table

ID Name

1 Xun

Code:

DataTable t=new DataTable ("Student Table");

DataRow R=t.newrow ();

r["id"]=2;

r["Name"]=XUN2;

T.rows.add (R);

4 "Add column

DATATABLE.COLUMNS.ADD ("Column name", Type.GetType ("Data type"));
5 "Reading column values from rows

datarow["column name"] or Datarow[datacolumn];
6 "Reading column values from a DataTable

DataTable table;

A, table. rows[i]["column name"]

b, table. Rows[i][i]

C, table[i]. Column names (column names are not quoted)

7 "read out a specific line

DataTable table;

Datarow[] selectrow=table. Select ("Column name = '" + holds a specific variable.) ToString () + "'");

Select one of the rows: selectrow[index]

Ii. Delete rows in a DataTable three methods: (DataTable.Rows.Remove (DataRow Dr), DataTable.Rows.RemoveAt (i), Datarow.delete ())

Delete Rows in a DataTable to be aware of indexing problems, there are generally two methods:
1 "With A For loop, note that the counter initial value is the table length, the self-decrement loop. DataTable.Rows.RemoveAt (i) should be noted.
2 "With the Select method of the DataTable, note that the parameter of the method is a string filter
A DataTable is required after 3 "Delete (). The Acceptechanges () method confirms a complete deletion, because delete () only flags the status of the corresponding column as deleted, and it can be passed through a DataTable. RejectChanges () rollback to make the row undelete. To delete multiple rows, you can use Delete () consecutively, and then use the Acceptechanges () method to confirm the deletion.

datable explanation, and usage