从SQLReader填充DataGridView [英] Filling a DataGridView from SQLReader

问题描述

一个大纲是我从一个SQL数据库中读取一些数据，并且想要在DataGridView中显示它在表单上。我已经确认有数据从数据库返回，但我不确定为什么这不出现。我已经跟随了许多来自互联网的教程，但到目前为止还没有工作

这里是我的代码

  Private Sub PopulateGrid（）
 Dim Con As New SqlClient.SqlConnection 
 Dim strCon As String = CropTrackMod.strConn 
 Dim strCommand As String =select * from客户
 
 
尝试
 Con.ConnectionString = strCon 
 Dim Cm As New SqlClient.SqlCommand（strCommand，Con）
 Con.Open（）
 Dim reader As SqlClient.SqlDataReader = Cm.ExecuteReader（）
 
'测试确认收到的数据
 reader.Read（）
 MsgBox（reader.Item（ContactName ））
 
 
 DataGridView1.AutoGenerateColumns = True 
 DataGridView1.DataSource = reader 
 DataGridView1.Refresh（）
 
 
 
 Catch ex As Exception 
 MessageBox.Show（ex.Message，Error）
 
最后
如果Con.State = ConnectionS tate.Open然后
 Con.Close（）
如果
结束尝试
 
 End Sub 
  

我也尝试实现一个datatable，但是在数据类型
上收到一个转换错误，任何帮助将不胜感激

谢谢你们

解决方案

你不能直接将数据库直接绑定到WinForms中的datagridview。相反，您可以使用读取器加载数据表，并将数据表分配给DataGridView的数据源

  Dim dt = new DataTable（） 
 dt.Load（reader）
 DataGridView1.AutoGenerateColumns = True 
 DataGridView1.DataSource = dt 
 DataGridView1.Refresh（）
  

Im a little stuck on some code that im writing

An outline is that i am reading some data in from an SQL database and wantint to display it in a DataGridView on a form. I have confirmed that there is data being returned from the database but am unsure as to why this isnt appearing. I have followed a number of tutorials from the internet but so far non have worked

here is my code

Private Sub PopulateGrid()
    Dim Con As New SqlClient.SqlConnection
    Dim strCon As String = CropTrackMod.strConn
    Dim strCommand As String = "select * from customer"


    Try
        Con.ConnectionString = strCon
        Dim Cm As New SqlClient.SqlCommand(strCommand, Con)
        Con.Open()
        Dim reader As SqlClient.SqlDataReader = Cm.ExecuteReader()

        'test to confirm data received
        reader.Read()
        MsgBox(reader.Item("ContactName"))


        DataGridView1.AutoGenerateColumns = True
        DataGridView1.DataSource = reader
        DataGridView1.Refresh()



    Catch ex As Exception
        MessageBox.Show(ex.Message, "Error")

    Finally
        If Con.State = ConnectionState.Open Then
            Con.Close()
        End If
    End Try

End Sub

i have also tried to implement a datatable but receive a conversion error on the data type any help would be appreciated

thanks guys

解决方案

You can't bind a datareader directly to a datagridview in WinForms. Instead you could load a datatable with your reader and assign the datatable to the datasource of the DataGridView

Dim dt = new DataTable()
dt.Load(reader)
DataGridView1.AutoGenerateColumns = True
DataGridView1.DataSource = dt
DataGridView1.Refresh()

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