如何使用datetimepicker在vb.net中查看两个日期之间的数据

我正在尝试使用datetimepicker查看两个日期之间的数据，当我尝试运行此代码时，我遇到一个错误，提示“从字符串转换日期和/或时间时转换失败”。如果有人能告诉我如何完成，我将非常感谢。

您需要检查SQL语句中的日期范围

私有子按钮2\u单击（发送者作为对象，e作为事件参数）处理按钮2。单击

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Dim cn As New SqlConnection
    Dim ds As New DataSet
    Dim dt As New DataTable
    Dim dfrom As DateTime
    Dim dto As DateTime
    Dim da As New SqlDataAdapter

    dfrom = dtpicker1.Text
    dto = dtpicker2.Text

    cn.ConnectionString = "Data Source=JMI-PC\SQLEXPRESS;Initial Catalog=student_system;User Id=ian;Password=rockstar"
    cn.Open()
    Dim str As String
    Format(dtpicker1.Text, "yyyy-MM-dd")
    Format(dtpicker2.Text, "yyyy-MM-dd")
    str = "select Exam_Date from class1  where Exam_Date= '" & dtpicker1.Text & "' and Exam_Date='" & dtpicker2.Text & "'"

    da = New SqlDataAdapter(str, cn)
    da.Fill(dt)
    DataGridView1.DataSource = dt
    DataGridView1.DataSource = dt


End Sub

Dim cn作为新的SqlConnection
Dim ds作为新数据集
Dim dt作为新数据表
Dim dfrom As DateTime=dtpicker1.Value
Dim dto As DateTime=dtpicker2.Value
cn.ConnectionString=“数据源=JMI-PC\SQLEXPRESS；初始目录=student\U系统；用户Id=ian；密码=rockstar”
cn.Open（）
Dim str As String=“从类别1中选择考试日期，其中考试日期>=”&格式（从“MM dd yyyy”开始的数据）和“‘和考试日期’我认为在确定日期范围时最好使用两者之间的时间，你认为呢？e、 g.从类别1中选择考试日期，其中考试日期在x和y之间。此外，您的代码似乎导致错误“Value”不是“Date”的成员，请删除值位
Dim cn As New SqlConnection
Dim ds As New DataSet
Dim dt As New DataTable
Dim dfrom As DateTime = dtpicker1.Value
Dim dto As DateTime = dtpicker2.Value


cn.ConnectionString = "Data Source=JMI-PC\SQLEXPRESS;Initial Catalog=student_system;User Id=ian;Password=rockstar"
cn.Open()
Dim str As String = "select Exam_Date from class1  where Exam_Date >= '" & Format(dFrom, "MM-dd-yyyy") & "' and Exam_Date <='" & Format(dto, "MM-dd-yyyy") & "'"

Dim da As SqlDataAdapter = New SqlDataAdapter(str, cn)
da.Fill(dt)
DataGridView1.DataSource = dt