C# DataView.RowStateFilter属性代码示例

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"]);
    }
}

//引入命名空间
using System;
using System.Data;
using System.Data.SqlClient;

class FindingDataRowViews
{
  public static void Main()
  {
    SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
    SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
    mySqlCommand.CommandText =
      "SELECT ID, FirstName, LastName " +
      "FROM Employee";
    SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
    mySqlDataAdapter.SelectCommand = mySqlCommand;
    DataSet myDataSet = new DataSet();
    mySqlConnection.Open();
    mySqlDataAdapter.Fill(myDataSet, "Employee");
    mySqlConnection.Close();
    DataTable employeeDT = myDataSet.Tables["Employee"];

    string filterExpression = "ID = 9";
    string sortExpression = "ID";
    DataViewRowState rowStateFilter = DataViewRowState.OriginalRows;

    DataView employeeDV = new DataView();
    employeeDV.Table = employeeDT;
    employeeDV.RowFilter = filterExpression;
    employeeDV.Sort = sortExpression;
    employeeDV.RowStateFilter = rowStateFilter;

    foreach (DataRowView myDataRowView in employeeDV)
    {
      for (int count = 0; count < employeeDV.Table.Columns.Count; count++)
      {
        Console.WriteLine(myDataRowView[count]);
      }
      Console.WriteLine("");
    }

    int index = employeeDV.Find("8");
    Console.WriteLine("8 found at index " + index + "\n");

    DataRowView[] employeeDRVs = employeeDV.FindRows("8");
    foreach (DataRowView myDataRowView in employeeDRVs)
    {
      for (int count = 0; count < employeeDV.Table.Columns.Count; count++)
      {
        Console.WriteLine(myDataRowView[count]);
      }
      Console.WriteLine("");
    }
  }
}