关于对DataTable进行操作的几个例子总结

第一个，这个主要是在一个表里选择一些行。但是，如果选择的依据是行的值为空白，也就是没有值的话，我不知条件怎么写，试了好多种方法，不行，所以最后也没用这个。这个方法的条件好像是模仿SQL里面的写法。

private void GetRowsByFilter()

{

    DataTable table = DataSet1.Tables["Orders"];

    // Presuming the DataTable has a column named Date.

    string expression;

    expression = "Date > '1/1/00'";

    DataRow[] foundRows;



    // Use the Select method to find all rows matching the filter.

    foundRows = table.Select(expression);



    // Print column 0 of each returned row.

    for(int i = 0; i < foundRows.Length; i ++)

    {

        Console.WriteLine(foundRows[i][0]);

    }

}

第二个，主要是用DataRow 的delete方法删除掉某些行，可以和第三个例子做一下对比

private void DemonstrateDeleteRow()

{

    // Create a simple DataTable with two columns and ten rows.

    DataTable table = new DataTable("table");

    DataColumn idColumn = new DataColumn("id",

        Type.GetType("System.Int32"));

    idColumn.AutoIncrement=true;

    DataColumn itemColumn = new DataColumn("item", 

        Type.GetType("System.String"));

    table.Columns.Add(idColumn);

    table.Columns.Add(itemColumn);



    // Add ten rows.

    DataRow newRow;

     

    for(int i = 0; i <10; i++)

    {

        newRow = table.NewRow();

        newRow["item"] = "Item " + i;

        table.Rows.Add(newRow);

    }

    table.AcceptChanges();



    DataRowCollection itemColumns = table.Rows;

    itemColumns[2].Delete();

    itemColumns[5].Delete();

    Console.WriteLine(itemColumns[3].RowState.ToString());



    // Reject changes on one deletion.

    itemColumns[3].RejectChanges();



    // Change the value of the column so it stands out.

    itemColumns[3]["item"] = "Deleted, Undeleted, Edited";



    // Accept changes on others.

    table.AcceptChanges();

}

第三个，vb写的例子，我也懒得改了。应用行集合的remove方法删除行。

Private Sub RemoveFoundRow(ByVal table As DataTable)

    Dim rowCollection As DataRowCollection = table.Rows



    ' Test to see if the collection contains the value.

    If rowCollection.Contains(TextBox1.Text) Then

        Dim foundRow As DataRow = rowCollection.Find(TextBox1.Text)

        rowCollection.Remove(foundRow)

        Console.WriteLine("Row Deleted")

    Else

        Console.WriteLine("No such row found.")

    End If

 End Sub