i want to display my database tables in tree view in my windowsform

Initialize the TreeView on the form. You can do this easily by dragging/dropping the treeview control from the control-bar in Visual Studio. Usually it is named as treeView1 when you do it by dragging/dropping. After that get the list of tables you want to display in the treeview; better pull that list from the database. When you have the list, you can use the following code to assign nodes to the treeview: (Assuming that you have list of table names in a List)

foreach(string tableName in tablesNameList) //tablesNameList is the list containing all the names of the tables
{
TreeNode treeNode = new TreeNode(tableName);

// if you want to add icon against each node or you want to assign some other properties you can do it here.
//After that you need to add that node to the treeview control. you can do it as below
treeView1.Nodes.Add(treeNode); // this line will add the node to the treeview control.

}

Hope I have answered your question.