如何将New Column with Value添加到现有DataTable？

3 回答

• 115

  没有For循环：

  Dim newColumn As New Data.DataColumn("Foo", GetType(System.String))     
  newColumn.DefaultValue = "Your DropDownList value" 
  table.Columns.Add(newColumn)
  

  这是未经测试的 . 我用过在线C＃conversion tool：

  System.Data.DataColumn newColumn = new System.Data.DataColumn("Foo", typeof(System.String));
  newColumn.DefaultValue = "Your DropDownList value";
  table.Columns.Add(newColumn);
  

  回复于 2024-04-19T16:21:59+08:00
• -2

  添加列并更新 DataTable 中的所有行，例如：

  DataTable tbl = new DataTable();
  tbl.Columns.Add(new DataColumn("ID", typeof(Int32)));
  tbl.Columns.Add(new DataColumn("Name", typeof(string)));
  for (Int32 i = 1; i <= 10; i++) {
      DataRow row = tbl.NewRow();
      row["ID"] = i;
      row["Name"] = i + ". row";
      tbl.Rows.Add(row);
  }
  DataColumn newCol = new DataColumn("NewColumn", typeof(string));
  newCol.AllowDBNull = true;
  tbl.Columns.Add(newCol);
  foreach (DataRow row in tbl.Rows) {
      row["NewColumn"] = "You DropDownList value";
  }
  //if you don't want to allow null-values'
  newCol.AllowDBNull = false;
  

  回复于 2024-04-19T16:21:59+08:00
• 12

  //Data Table
  
   protected DataTable tblDynamic
          {
              get
              {
                  return (DataTable)ViewState["tblDynamic"];
              }
              set
              {
                  ViewState["tblDynamic"] = value;
              }
          }
  //DynamicReport_GetUserType() function for getting data from DB
  
  
  System.Data.DataSet ds = manage.DynamicReport_GetUserType();
                  tblDynamic = ds.Tables[13];
  
  //Add Column as "TypeName"
  
                  tblDynamic.Columns.Add(new DataColumn("TypeName", typeof(string)));
  
  //fill column data against ds.Tables[13]
  
  
                  for (int i = 0; i < tblDynamic.Rows.Count; i++)
                  {
  
                      if (tblDynamic.Rows[i]["Type"].ToString()=="A")
                      {
                          tblDynamic.Rows[i]["TypeName"] = "Apple";
                      }
                      if (tblDynamic.Rows[i]["Type"].ToString() == "B")
                      {
                          tblDynamic.Rows[i]["TypeName"] = "Ball";
                      }
                      if (tblDynamic.Rows[i]["Type"].ToString() == "C")
                      {
                          tblDynamic.Rows[i]["TypeName"] = "Cat";
                      }
                      if (tblDynamic.Rows[i]["Type"].ToString() == "D")
                      {
                          tblDynamic.Rows[i]["TypeName"] = "Dog;
                      }
                  }
  

  回复于 2024-04-19T16:21:59+08:00