第一个下一个上一个按钮的代码和页面窗口C#应用程序中的显示数据 [英] Code for first next last previous button and display data in page windows C# application
问题描述
我创建了windows c#应用程序。其中我把按钮放在第一个,下一个,最后一个,上一个。
现在我想显示从数据库中获取记录,并在页面中显示。
当我点击第一个按钮然后在加载时间数据显示首先。当我点击最后一个然后数据显示最后一个记录,当我点击上一个然后数据显示之前,当我点击下一个然后在c#windows应用程序接下来显示数据。
请帮助我...
我尝试了什么:
i尝试创建代码,但没有成功。如何使用for循环来使用它并在页面的加载时间内显示数据。
i create windows c# application. in which i put button like first,next, last,previous.
now i want to display record fetch from database , and show in page.
when i click first button then on load time data display first. when i click last then data display last record, when i click previous then data dispaly previous, and when i click next then display data next in c# windows application.
pls help me...
What I have tried:
i tried to create code, but not get succcess. how can i use for loop to use that and display data in load time of page.
推荐答案
你不使用循环。
究竟如何做到这一点取决于许多因素,例如你如何获取数据,涉及多少数据,以及你的数据库包含的内容。
但是一种方法是:
确保您的数据库包含Id列,ID为IDENTITY。
在数据库中设置一个类级别int,名为lastRow
并将其设置为-1。
当您从数据库中获取要显示的单行时,请使用以下内容:
You don't use a loop.
Exactly how to do this depends on a number of factors, such as how you are fetching your data, how much data is involved, and what exactly your DB contains.
But one way would be:
Make sure your DB contains an Id column, with is IDENTITY.
Set up a class level int in your DB calledlastRow
and set it to -1.
When you fetch a single row from the DB to display, use something like:
SELECT TOP 1 * FROM MyTable WHERE Id > lastRow ORDER BY ID ASC
如果您获得任何行,请使用ID值加载lastRow。
对于Next,它是相同的查询。
对于之前的:
If you get any rows, load lastRow with the ID value.
For "Next" it's the same query.
For previous its:
SELECT TOP 1 * FROM MyTable WHERE Id < lastRow ORDER BY ID DESC
首先:
First:
SELECT TOP 1 * FROM MyTable ORDER BY ID ASC
Lst:
Lst:
SELECT TOP 1 * FROM MyTable ORDER BY ID DESC
使用此示例建立你的表格
use this example build your Form
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
DataTable dt = new DataTable();
int index = 0;
int last = 0;
private void Form1_Load(object sender, EventArgs e)
{
dt.Columns.Add("FirstName");
dt.Columns.Add("LastName");
dt.Rows.Add("Moto", "Nexus");
dt.Rows.Add("Apple", "Iphone");
dt.Rows.Add("Sony", "Vaio");
dt.Rows.Add("Samsung", "Edge");
index = 0;
last = dt.Rows.Count -1;
PopulateData();
}
private void btnFirst_Click(object sender, EventArgs e)
{
index = 0;
PopulateData();
}
private void btnLast_Click(object sender, EventArgs e)
{
index = last - 1;
PopulateData();
}
private void btnPrev_Click(object sender, EventArgs e)
{
index--;
index = index <0? 0:index;
PopulateData();
}
private void btnNext_Click(object sender, EventArgs e)
{
index++;
index = index > last? last : index;
PopulateData();
}
private void PopulateData()
{
DataRow row = dt.Rows[index];
string firstName = row["FirstName"].ToString();
string lastName = row["LastName"].ToString();
txtFirstName.Text = firstName;
txtLastName.Text = lastName;
}
}
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