如何在Datable中创建新列并将值分配给新创建的列行 [英] How Create a new Column in a Datable and assign value to the newly created column row

问题描述

我已经从这样的数据库中生成了一个数据表

来源目的地车辆费率
-------------------------------------------------- -
a b XXX 500
a c xxx 400


在数据表中添加一列(New_Rate)并分配值后.

来源目的地车辆费率新价格
-------------------------------------------------- ------------------------------
a b XXX 500 1000
a c xxx 400800

这是我的代码段:

i have generated a datatable from database like this

source destination vehicle Rate
---------------------------------------------------
a b XXX 500
a c xxx 400


After add a column (New_Rate) in the datatable and assign value.

source destination vehicle Rate New_Rate
--------------------------------------------------------------------------------
a b XXX 500 1000
a c xxx 400 800

Here is my code snippet:

SqlDataAdapter adp2 = new SqlDataAdapter("select source, destination, vehicle, rate from pickupdroptariff order by source", conn);
        DataTable dt2 = new DataTable();
        adp2.Fill(dt2);
        dt2.Columns.Add("Rate_New");
        int veh_rate=0;
        if (dt2.Rows.Count > 0)
        {
            for (int j = 0; j < dt2.Rows.Count; j++)
            {
                if(dt2.Rows[j][2].ToString()=="Small Car")
                {
                    veh_rate = Convert.ToInt32(dt2.Rows[j][3].ToString());
                    veh_rate = veh_rate + small;
                    //DataRow row = null;
                    //row[4] = veh_rate.ToString();
                    //dt2.Rows.Add(row);

                    dt2.Rows.Add("small",veh_rate.ToString());
                }
                if(dt2.Rows[j][2].ToString()=="Regular Car")
                {
                    veh_rate = Convert.ToInt32(dt2.Rows[j][3].ToString());
                    veh_rate = veh_rate + regular;
                    dt2.Rows.Add("Regular", veh_rate.ToString());
                }
                if(dt2.Rows[j][2].ToString()=="Luxury Car")
                {
                    veh_rate = Convert.ToInt32(dt2.Rows[j][3].ToString());
                    veh_rate = veh_rate + luxury;
                    dt2.Rows.Add("Luxury", veh_rate.ToString());
                }
            }
        }
        GridView1.DataSource = dt2;
        GridView1.DataBind();

其中:
dt2是数据表，
veh_rate存储车辆费率

但是新记录将添加到先前记录的下面.

请帮助我，非常感谢.

Where:
dt2 is the datatable,
veh_rate stores vehicle rate

But new records are added below of the previous records.

Please help me, thank you very much.

推荐答案

朋友您好，

下面的代码可以帮助您...


DataTable dt4 = new DataTable();

Hi friend,

This below code may help you...


DataTable dt4 = new DataTable();

dt4.Columns.Add("Eid");
       dt4.Columns.Add("Emp_Name");
       dt4.Columns.Add("uname");
       dt4.Columns.Add("Pwd");

foreach(Gv.Rows中的GridViewRow行)
{
dr3 = dt4.NewRow();
标签Eid =(标签)row.FindControl("lblEid");
TextBox Ename =(TextBox)row.FindControl("txtEmpname");
TextBox Uname =(TextBox)row.FindControl("txtUname");
TextBox pwd =(TextBox)row.FindControl("txtPwd");
dr3 [0] = Eid.Text;
dr3 [1] = Ename.Text;
dr3 [2] = Uname.Text;
dr3 [3] = pwd.Text;
dt4.Rows.Add(dr3);

}
dr3 = dt4.NewRow();
dt4.Rows.Add(dr3);
dt.Clear();
Session.Remove("dt");
dt = dt4.Copy();
会话["dt"] = dt4;
Gv.DataSource = dt4;
Gv.DataBind();

foreach (GridViewRow row in Gv.Rows)
{
dr3 = dt4.NewRow();
Label Eid = (Label)row.FindControl("lblEid");
TextBox Ename = (TextBox)row.FindControl("txtEmpname");
TextBox Uname = (TextBox)row.FindControl("txtUname");
TextBox pwd = (TextBox)row.FindControl("txtPwd");
dr3[0] = Eid.Text;
dr3[1] = Ename.Text;
dr3[2] = Uname.Text;
dr3[3] = pwd.Text;
dt4.Rows.Add(dr3);

}
dr3 = dt4.NewRow();
dt4.Rows.Add(dr3);
dt.Clear();
Session.Remove("dt");
dt = dt4.Copy();
Session["dt"] = dt4;
Gv.DataSource = dt4;
Gv.DataBind();

更改原始表以通过sql添加新列，

ALTER the original table to add the new column via sql,

'add column
ALTER TABLE [dbo].[pickupdroptariff] 
add  [Rate_New] [int]

然后使用UPDATE为每一行填充新列.

then use UPDATE to fill in the new column for each row.

这篇关于如何在Datable中创建新列并将值分配给新创建的列行的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！