如何在VB.NET中使用sendmessage API设置最小和最大日期 [英] How to use sendmessage API for set min and max date in VB.NET

问题描述

嗨
i想要从所选年份设置datetimepicker的最小和最大日期。



提前付款



我尝试过：



我的代码：

Hi i want to set min and max date of datetimepicker from selected year.

Thanks in Advance

What I have tried:

My Code:

Public Structure SYSTEMTIME
        Dim wYear As Integer
        Dim wMonth As Integer
        Dim wDayOfWeek As Integer
        Dim wDay As Integer
        Dim wHour As Integer
        Dim wMinute As Integer
        Dim wSecond As Integer
        Dim wMilliseconds As Integer

    End Structure

    Public Declare Function SendMessage Lib "user32.dll" _
                         Alias "SendMessageA" _
                         (ByVal hWnd As IntPtr, ByVal wMsg As Int32, ByVal wParam As Integer, ByVal lParam As SYSTEMTIME) As IntPtr
    Public Const DTM_SETRANGE = &H1004&
    Public Const GDTR_MIN = 1
    Public Const GDTR_MAX = 2

  Dim TimeArray(1) As SYSTEMTIME
        Dim result As IntPtr
        'Dim trdt As Date

        ' Define first minimum date.
        TimeArray(0).wDay = Format(dt, "dd")
        TimeArray(0).wMonth = Format(dt, "MM")
        TimeArray(0).wYear = Format(dt, "yyyy")

        ' Define second maximum date.
        TimeArray(1).wDay = Format(Dt1, "dd")
        TimeArray(1).wMonth = Format(Dt1, "MM")
        TimeArray(1).wYear = Format(Dt1, "yyyy")

        result = SendMessage(Me.dtpFrom.Handle, DTM_SETRANGE,
   GDTR_MIN + GDTR_MAX, TimeArray(0))

显示错误ror尝试读取或写入受保护的内存。这通常表明其他内存已损坏

Its showing error "Attempted to read or write protected memory. This is often an indication that other memory is corrupt

推荐答案

为什么？ DateTimePicker类 [ ^ 已经有 MaxDate [ ^ ]和 MinDate [ ^ ]属性。只需使用它们。

Why? The DateTimePicker class[^] already has MaxDate[^] and MinDate[^] properties. Just use those.

Me.dtpFrom.MinDate = dt
Me.dtpFrom.MaxDate = dt1

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