Question

我从数据库中获取结果以填充Combobox并确保一切正常。接下来我要做的就是从这个Combobox中选择一些东西，然后在DataGridView上显示我从CB中选择的一些信息。

这是我现在正在使用的代码

        SQLCon = New SqlConnection
        SQLCon.ConnectionString = "....."
        Try
            SQLCon.Open()
            Dim Query As String
            Query = "SELECT Filetype FROM infofile GROUP BY Filetype"
            SqlCmd = New SqlCommand(Query, SQLCon)
            SQLDataReader = SqlCmd.ExecuteReader
            While SQLDataReader.Read
                Dim fileType = SQLDataReader.GetString(0)
                DataGridView1.DataSource = ComboBox1.Items.Add(fileType)
            End While
            SQLCon.Close()
        Catch ex As SqlException
            MsgBox(ex.Message)
        Finally
            SQLCon.Dispose()
        End Try

Answer 1

首先使用您的代码填充ComboBox：

SQLCon = New SqlConnection
SQLCon.ConnectionString = "....."
Try
    SQLCon.Open()
    Dim Query As String
    Query = "SELECT Filetype FROM infofile GROUP BY Filetype"
    SqlCmd = New SqlCommand(Query, SQLCon)
    SqlDataReader = SqlCmd.ExecuteReader
    While SqlDataReader.Read
        Dim fileType = SqlDataReader.GetString(0)
        ComboBox1.Items.Add(fileType)
    End While
    SQLCon.Close()
Catch ex As SqlException
    MsgBox(ex.Message)
Finally
    SQLCon.Dispose()
End Try

创建Function，将数据从数据库返回到DataGridView，其中ComboBox更改数据如下：

Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
    DataGridView1.DataSource = FillDataGridView(ComboBox1.Text)
End Sub

Function FillDataGridView(valueComboBox As String) As DataTable
    SQLCon = New SqlConnection
    SQLCon.ConnectionString = "....."
    Dim table As New DataTable
    Try
        SQLCon.Open()
        Dim Query As String
        Query = "SELECT Filetype FROM infofile where Filetype=@Filetype"
        SqlCmd = New SqlCommand(Query, SQLCon)
        SqlCmd.Parameters.Add("@Filetype", SqlDbType.VarChar).Value = valueComboBox
        Dim adapter As New SqlDataAdapter(SqlCmd)
        adapter.Fill(table)
        SQLCon.Close()
        Return table
    Catch ex As SqlException
        MsgBox(ex.Message)
        Return table
    Finally
        SQLCon.Dispose()
    End Try
End Function

您可以根据需要更改查询以提供更多字段

填充组合框并在DataGridView上获取结果

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