C # operations TreeView, Database read data (2017-12-12 learning Note)

1. Learn the points of knowledge:

Database operation Syntax:

SqlConnection Database Connection Object

SqlConnection con =new SqlConnection ();

Con.open ();//Open database

SqlCommand Database Operations Command

SQlCommand com =new SQlCommand ();

com.commandtype=com.commandtext;//operation type is a database SQL statement

com.commandtext= "SELECT * from TB";//SQL statement executed

Com. Parameters.Add ("@id", SqlDbType.Int);//define an input parameter @id the search value for the SQL statement such as: SELECT * from TB where [email protected] SqlDbType. Int defines the field type

Com. ExecuteReader ();//Execute DATABASE statement.

Sqldataadapater//To populate the dataset and update the database commands

Sqldataadapater adapater =new sqldataadapater ("SELECT * from TB", con);//Execute DATABASE statement, return a stream

DataSet _ds=new DataSet ();

Adapater. Fill (_ds);//Data fills into a dataset or

Adapater=com. ExecuteReader ();

Whlie (Adapater. Read ())//Adapater. Read () indicates that the forward view record is equivalent to _ds. Table[0]. rows[i]["id"].tostring ()

{

}

Adapater. Dispose ();//Release resources

Con. Close ();//Closing database connection

TreeView Knowledge Point

TreeNode tr=new TreeNode ("all");//define a tree node

Tr. Nodes.Add ("Level Two Node");

Tr. Nodes[index]. Nodes.Add ("")//index the location of the Add node

Treeview. The Checkboxs=true;//property check box displays

Treeview. imagelist=imagelist1;//Add picture Display imagelist1 is a picture control on the toolbar

Treeview. Expanall ();//Expand All nodes

C # operations TreeView, Database read data (2017-12-12 learning Note)