选择数据表的某些列

6 回答

• 25

  首先将表存储在视图中，然后从该视图中选择列到新表中 .

  System.Data.DataTable table = new System.Data.DataTable();
  for (int i = 1; i <= 11; i++)
      table.Columns.Add("col" + i.ToString());
  
  for (int i = 0; i < 100; i++)
  {
      System.Data.DataRow row = table.NewRow();
      for (int j = 0; j < 11; j++)
          row[j] = i.ToString() + ", " + j.ToString();
      table.Rows.Add(row);
  }
  
  System.Data.DataView view = new System.Data.DataView(table);
  System.Data.DataTable selected = view.ToTable("Selected", false, "col1", "col2", "col6", "col7", "col3");
  

  使用示例数据来测试我找到的这个方法：Create ADO.NET DataView showing only selected Columns

  回复于 2024-04-27T10:08:33+08:00
• 35

  我们也可以这样试试，

  string[] selectedColumns = new[] { "Column1","Column2"};
  
   DataTable dt= new DataView(fromDataTable).ToTable(false, selectedColumns);
  

  回复于 2024-04-27T10:08:33+08:00
• 1

  我要问的问题是，如果不需要，为什么要在DataTable中包含额外的列？

  也许您应该修改SQL select语句，以便在填充DataTable时查看您要查找的特定条件 .

  您还可以使用LINQ将DataTable作为Enumerable进行查询，并创建仅表示某些列的List对象 .

  除此之外，隐藏您不需要的DataGridView列 .

  回复于 2024-04-27T10:08:33+08:00
• -1

  这是匿名输出记录的工作示例，如果您有任何问题，请在下面发表评论：

  public partial class Form1：Form {DataTable table;

  public Form1()
      {
          InitializeComponent();
  
          #region TestData
          table = new DataTable();
          table.Clear();
  
          for (int i = 1; i < 12; ++i)
              table.Columns.Add("Col" + i);
          for (int rowIndex = 0; rowIndex < 5; ++rowIndex)
          {
              DataRow row = table.NewRow();
              for (int i = 0; i < table.Columns.Count; ++i)
                  row[i] = String.Format("row:{0},col:{1}", rowIndex, i);
              table.Rows.Add(row);
          }
          #endregion
  
          bind();
      }
  
      public void bind()
      {
          var filtered = from t in table.AsEnumerable()
                         select new
                         {
                             col1 = t.Field<string>(0),//column of index 0 = "Col1"
                             col2 = t.Field<string>(1),//column of index 1 = "Col2"
                             col3 = t.Field<string>(5),//column of index 5 = "Col6"
                             col4 = t.Field<string>(6),//column of index 6 = "Col7"
                             col5 = t.Field<string>(4),//column of index 4 = "Col3"
                         };
          filteredData.AutoGenerateColumns = true;
          filteredData.DataSource = filtered.ToList();
      }
  }
  

  回复于 2024-04-27T10:08:33+08:00
• 0

  您可以创建一个如下所示的方法：

  public static DataTable SelectedColumns(DataTable RecordDT_, string col1, string col2)
      {
          DataTable TempTable = RecordDT_;
  
          System.Data.DataView view = new System.Data.DataView(TempTable);
          System.Data.DataTable selected = view.ToTable("Selected", false, col1, col2);
          return selected;
      }
  

  您可以返回尽可能多的列 . 只需将列添加为调用参数，如下所示：

  public DataTable SelectedColumns(DataTable RecordDT_, string col1, string col2,string col3,...)
  

  并将参数添加到此行：

  System.Data.DataTable selected = view.ToTable("Selected", false,col1, col2,col3,...);
  

  然后简单地实现以下功能：

  DataTable myselectedColumnTable=SelectedColumns(OriginalTable,"Col1","Col2",...);
  

  谢谢...

  回复于 2024-04-27T10:08:33+08:00
• 0

  DataView dv = new DataView(Your DataTable);
  
  DataTable dt = dv.ToTable(true, "Your Specific Column Name");
  

  dt仅包含选定的列值 .

  回复于 2024-04-27T10:08:33+08:00