取dataview中的行的操作

在对数据库的操作中,对dataview使用越来越多,慢慢对内存中的数据表的操作也掌握的更多了,这样很有利于数据的重复使用,减少操作物理数据库的次数.

/// <summary>
  /// 初始化TreeView 的 RootNode
  /// </summary>
  private void InitTreeRootNode(TreeNodeCollection TNC)
  {
   DataView dataView  = new DataView();
   dataView     = dataTbl1.Copy().DefaultView;
   dataView.RowFilter = "ClassParentID = ClassID";
   dataView.Sort="ClassOrder asc,classid desc";

   foreach(DataRowView drv in dataView)
   { 
    TreeNode tn    = new TreeNode();
    tn.ID     = drv["ClassID"].ToString();
    tn.Text     = "<span onmousemove=javascript:title='"+drv["ClassName"]+"'>"+drv["ClassName"].ToString()+"</span>";
    tn.ImageUrl    = GetIcon(drv["ClassType"].ToString());
    tn.NavigateUrl = "Switch.aspx?Action=1&ClassID="+drv["ClassID"].ToString();
    tn.Target      = "MainFrame";
    TNC.Add(tn);
    InitChildNodeDataTable(Int32.Parse(tn.ID.ToString()));
    InitTreeChildNode(tn.Nodes,tn.ID);
   }
   dataTbl1 = null;
   dataTbl2 = null;
  } 

 

这里是对dataview中的行的操作

static private void DemonstrateRowState()
{
    // Create a DataTable with one column.
    DataTable dataTable = new DataTable("dataTable");
    DataColumn dataColumn = new DataColumn("dataColumn");
    dataTable.Columns.Add(dataColumn);

    // Add ten rows.
    DataRow dataRow;
    for (int i = 0; i < 10; i++)
    {
        dataRow = dataTable.NewRow();
        dataRow["dataColumn"] = "item " + i;
        dataTable.Rows.Add(dataRow);
    }
    dataTable.AcceptChanges();

    // Create a DataView with the table.
    DataView dataView = new DataView(dataTable);

    // Change one row's value:
    dataTable.Rows[1]["dataColumn"] = "Hello";

    // Add one row:
    dataRow = dataTable.NewRow();
    dataRow["dataColumn"] = "World";
    dataTable.Rows.Add(dataRow);

    // Set the RowStateFilter to display only added and modified rows.
    dataView.RowStateFilter = DataViewRowState.Added
        | DataViewRowState.ModifiedCurrent;

    // Print those rows. Output = "Hello" "World";
    PrintView(dataView, "ModifiedCurrent and Added");

    // Set filter to display on originals of modified rows.
    dataView.RowStateFilter = DataViewRowState.ModifiedOriginal;
    PrintView(dataView, "ModifiedOriginal");

    // Delete three rows.
    dataTable.Rows[1].Delete();
    dataTable.Rows[2].Delete();
    dataTable.Rows[3].Delete();

    // Set the RowStateFilter to display only Added and modified rows.
    dataView.RowStateFilter = DataViewRowState.Deleted;
    PrintView(dataView, "Deleted");

    //Set filter to display only current.
    dataView.RowStateFilter = DataViewRowState.CurrentRows;
    PrintView(dataView, "Current");

    // Set filter to display only unchanged rows.
    dataView.RowStateFilter = DataViewRowState.Unchanged;
    PrintView(dataView, "Unchanged");

    // Set filter to display only original rows.
    dataView.RowStateFilter = DataViewRowState.OriginalRows;
    PrintView(dataView, "OriginalRows");
}

static private void PrintView(DataView dataView, string label)
{
    Console.WriteLine("\n" + label);
    for (int i = 0; i < dataView.Count; i++)
    {
        Console.WriteLine(dataView[i]["dataColumn"]);
    }
}