帮助我解决如何使用文本框和按钮搜索带有代码格式的记录的代码 [英] help me for codes on how to search record with dis codes format with ah textbox and a button

问题描述

  Imports  MySql.Data.MySqlClient 
  Public  类 Form1 
 公开 mycon  As  新 MySqlConnection 
 公开 myadap  As  新 MySqlDataAdapter 
 公开 mycmd  As  新 MySqlCommand 
 公共 myds  As  新 DataSet 
 公开 rec 正如 整数 
 公共 sb 正如 布尔 
 < span class =code-keyword>公共 idnum 作为 字符串 
 
 私有  Sub  Form1_Load（ ByVal  sender  As  System。 Object ， ByVal  e  As  System.EventArgs）句柄  MyBase 。加载
 调用 connection（）
 调用 display（）
 
 结束  Sub  
 
  Sub  connection（）
 mycon =  New  MySqlConnection 
 mycon.ConnectionString =    server = localhost; user id = root; password =; database = dbase 
 mycon.Open（）
 mycmd.Connection = mycon 
 mycmd.CommandText =   select * from tbl 
 myds = 新 DataSet 
 myadap.SelectCommand = mycmd 
 myadap.Fill（myds，  tbl）
 
 rec =  0  
 结束  Sub  
  Sub  display（）
 dg.DataSource = myds.Tables（  tbl）
 txtId.Text = myds.Tables（  tbl）。行（rec）.Item（  Id）
 txtn.Text = myds.Tables（  tbl）。行（rec ）.Item（  name）
 txtage.Text = myds.Tables（  tbl）。行（rec）.Item（ 年龄）
 cmdedit.Enabled =  True  
 cmdadd.Enabled =  True  
 结束  Sub  
 
 私人  Sub  cmdsave_Click（ ByVal  sender  As 系统。对象， ByVal  e  As  System.EventArgs）句柄 cmdsave.Click 
 如果 txtId.Text =   或 txtn.Text =   或 txtage .Text =   然后 
 MsgBox（ 完成所有字段，MsgBoxStyle.Information， ）
  ElseIf  sb =  True  然后 
 mycmd.Connection = mycon 
 mycmd.CommandText =  插入`tbl`（`id`，`name`，`age`）值（'& txtId.Text&  '，'& txtn.Text&  '，'& txtage.Text&  '） 
 mycmd.ExecuteNonQuery（）
 mycon.Close（） 
 MsgBox（  SAVED !!，MsgBoxStyle.Information， ）
 致电 connection（）
 致电 display（）
 
 其他 

解决方案

我的问题仍然在评论区域。但是，这就是你接收数据的方式。

这里不需要很多注释，因为与上面的代码相比，代码是自我解释的。

  Imports  MySql.Data .MySqlClient 
 
 
 '  MySqlConnection类用于连接MySQL数据库。 
 
 
  Dim  con  As  MySqlConnection =  New  MySqlConnection（  Data Source = localhost; Database = test; User ID = root;密码= mysql;）' 连接字符串 
 
 
 ' 从MySQL数据库中删除DataGridview中的记录。从MySQL数据库中显示VB.Net中的记录 
 
 
 私有  Sub  DisplayRecords_Click（ ByVal  sende r 作为系统。对象， ByVal  e  As  System.EventArgs）句柄 Button1.Click 
  Dim  con  As  MySqlConnection = 新 MySqlConnection（ 数据源= localhost;数据库=测试;用户ID = root;密码= mysql;）
  Dim  sql  As  MySqlCommand = 新 MySqlCommand（  SELECT * FROM userreg，con）
 
  Dim  ds  As  DataSet = 新 DataSet（）
 
 昏暗 DataAdapter1  As  MySqlDataAdapter = 新 MySqlDataAdapter（）
 
 con.Open（ ）
 
 DataAdapter1.SelectCommand = sql 
 
 DataAdapter1.Fill（ds，  Product）
 
 DataGridView1.DataSource = ds 
 
 DataGridView1.DataMember =   Product 
 
 con.Close（）
 
  End   Sub  

要使用参数化查询，您可以看到一个简短的以下的例子。

  Dim  VendorID 正如 整数 =  1  
  Dim  SKU  As  整数 =  123  
  Dim  sql  As   String  =   UPDATE SKU SET VENDORID = @ VENID WHER SKU = @ eSKU 
 < span class =code-keyword> Dim  sqlcommand  As  新 SqlClient.SqlCommand 
 使用 sqlcommand 
 .CommandType = CommandType.Text 
 .CommandText = sql 
 .Connection = connection 
 ' 您可以在下面看到您的sql查询字符串如何使用占位符作为参数 
  ' 您可以在下面看到它们的工作原理。花一些时间研究这个并查看 
 ' 参数化查询语句。 
 .Parameters.AddWithValue（  @ VENID，VendorID）
。参数.AddWithValue（  @ eSKU，SKU）
 结束   

希望这有帮助。

Imports MySql.Data.MySqlClient
Public Class Form1
Public mycon As New MySqlConnection
Public myadap As New MySqlDataAdapter
Public mycmd As New MySqlCommand
Public myds As New DataSet
Public rec As Integer
Public sb As Boolean
Public idnum As String
 
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Call connection()
Call display()

End Sub

Sub connection()
mycon = New MySqlConnection
mycon.ConnectionString = "server=localhost;user id=root;password=;database=dbase"
mycon.Open()
mycmd.Connection = mycon
mycmd.CommandText = "select * from tbl"
myds = New DataSet
myadap.SelectCommand = mycmd
myadap.Fill(myds, "tbl")
 
rec = 0
End Sub
Sub display()
dg.DataSource = myds.Tables("tbl")
txtId.Text = myds.Tables("tbl").Rows(rec).Item("Id")
txtn.Text = myds.Tables("tbl").Rows(rec).Item("name")
txtage.Text = myds.Tables("tbl").Rows(rec).Item("Age")
cmdedit.Enabled = True
cmdadd.Enabled = True
End Sub

Private Sub cmdsave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdsave.Click
        If txtId.Text = "" Or txtn.Text = "" Or txtage.Text = "" Then
            MsgBox("Complete all Fields", MsgBoxStyle.Information, "")
        ElseIf sb = True Then
            mycmd.Connection = mycon
            mycmd.CommandText = "insert into `tbl`(`id`,`name`,`age`)values('" & txtId.Text & "','" & txtn.Text & "','" & txtage.Text & "')"
            mycmd.ExecuteNonQuery()
            mycon.Close()
            MsgBox("SAVED!!", MsgBoxStyle.Information, "")
            Call connection()
            Call display()
            
        Else

解决方案

My question still stands in the comments area. However, this is how you would receive data.
Not to many comments needed here as the code is self explanatory compared to the code you have above.

Imports MySql.Data.MySqlClient


'MySqlConnection Class is used to connect to MySQL database.


Dim con As MySqlConnection = New MySqlConnection("Data Source=localhost;Database=test;User ID=root;Password=mysql;")'Connection string


'Disaplay Records in DataGridview from MySQL Database.Display Records in VB.Net from MySQL Database


Private Sub DisplayRecords_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim con As MySqlConnection = New MySqlConnection("Data Source=localhost;Database=test;User ID=root;Password=mysql;")
        Dim sql As MySqlCommand = New MySqlCommand("SELECT * FROM userreg", con)

        Dim ds As DataSet = New DataSet()

        Dim DataAdapter1 As MySqlDataAdapter = New MySqlDataAdapter()

        con.Open()

        DataAdapter1.SelectCommand = sql

        DataAdapter1.Fill(ds, "Product")

        DataGridView1.DataSource = ds

        DataGridView1.DataMember = "Product"

        con.Close()

    End Sub

To use Parametrized queries, you can see a brief example of this below.

Dim VendorID As Integer = 1
        Dim SKU As Integer = 123
        Dim sql As String = "UPDATE SKU SET VENDORID=@VENID WHERE SKU=@eSKU"
        Dim sqlcommand As New SqlClient.SqlCommand
        With sqlcommand
            .CommandType = CommandType.Text
            .CommandText = sql
            .Connection = connection
'You can see below how your sql query string uses placeholders for the parameters
'and you can see how they work below. Take some time to study this and look in
'Parametrized query statements.
            .Parameters.AddWithValue("@VENID", VendorID)
            .Parameters.AddWithValue("@eSKU", SKU)
        End With

Hope this helps.

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