我正在尝试将vb.net应用程序转换为C＃，但是当我转换代码以检查日期单元格是否在两个devexpress dateedits之间时，它将运行下一个代码，但是不幸的是，我收到一条错误消息，指出说：
运算符'<='不能应用于类型为'object'和'object'的操作数
我在互联网上进行搜索，但找不到解决问题的方法
这是我的C＃代码：
foreach (DataRowView dr in Logs_Grid.Items)
{
SqlCommand cmd2 = new SqlCommand();
SqlDataReader rd2;
DataSet ds2 = new DataSet();
// Dim CustomerIDfromtheTbl
ds2.Clear();
cmd2.Connection = conn;
// SELECT TOP 1 WITH TIES * FROM International ORDER BY News_ID DESC
cmd2.CommandText = "SELECT * FROM att_download where Machine_IP = '" + IP_txt.Text + "' and User_ID = '" + dr[0] + "' and Verify_Date = '" + Format(Convert.ToDateTime(dr[1]), ("yyyy-MM-dd")) + "' and Verify_Time = '" + Format(Convert.ToDateTime(dr[2]), "HH:mm:ss") + "' ";
rd2 = cmd2.ExecuteReader();
// SELECT ID FROM INVOICE_HEAD ORDER BY ID DESC LIMIT 1
if (rd2.HasRows)
{
rd2.Read();
// MessageBox.Show("موجود مسبقا" + " " + rd2.Item("User_ID").ToString)
rd2.Close();
}
else if (dr[1] >= From_Date.EditValue && dr[1] <= To_Date.EditValue)
{
SqlCommand cmd4 = new SqlCommand();
SqlDataReader rd4;
DataSet ds4 = new DataSet();
// Dim CustomerIDfromtheTbl
ds4.Clear();
cmd4.Connection = conn;
// SELECT TOP 1 WITH TIES * FROM International ORDER BY News_ID DESC
cmd4.CommandText = "select * from Att_Users where user_code ='" + dr[0] + "' and machine_ip ='" + IP_txt.Text + "'";
rd4 = cmd4.ExecuteReader();
// SELECT ID FROM INVOICE_HEAD ORDER BY ID DESC LIMIT 1
if (rd4.HasRows)
{
rd4.Read();
string sqlString = "insert into att_download (User_ID,Verify_Date,Verify_Time,Verify_Type,Verify_State,WorkCode,CREATE_USER,CREATE_DATE,CREATE_TIME,User_Name,Emp_Code,Machine_IP) "
+ "values (@User_ID,@Verify_Date,@Verify_Time,@Verify_Type,@Verify_State,@WorkCode,@CREATE_USER,@CREATE_DATE,@CREATE_TIME,@User_Name,@Emp_Code,@Machine_IP)";
using (SqlCommand cmd = new SqlCommand(sqlString, conn))
{
DateTime now = DateTime.Now;
cmd.Parameters.Add(new SqlParameter("@User_ID", dr[0]));
cmd.Parameters.Add(new SqlParameter("@Verify_Date", dr[1]));
cmd.Parameters.Add(new SqlParameter("@Verify_Time", dr[2]));
cmd.Parameters.Add(new SqlParameter("@Verify_Type", dr[3]));
cmd.Parameters.Add(new SqlParameter("@Verify_State", dr[4]));
cmd.Parameters.Add(new SqlParameter("@WorkCode", dr[5]));
cmd.Parameters.Add(new SqlParameter("@CREATE_USER", Main_UserName));
cmd.Parameters.Add(new SqlParameter("@CREATE_DATE", DateTime.Today.ToString("yyyy-MM-dd")));
cmd.Parameters.Add(new SqlParameter("@CREATE_TIME", now.ToString("HH:mm:ss")));
cmd.Parameters.Add(new SqlParameter("@User_Name", rd4["user_name"]));
cmd.Parameters.Add(new SqlParameter("@Emp_Code", rd4["Emp_Code"]));
cmd.Parameters.Add(new SqlParameter("@Machine_IP", IP_txt.Text));
cmd.ExecuteNonQuery();
}
rd4.Close();
}
}
这是vb.net代码：
For Each dr As DataRowView In Logs_Grid.Items
Dim cmd2 As New SqlCommand
Dim rd2 As SqlDataReader
Dim ds2 As New DataSet
'Dim CustomerIDfromtheTbl
ds2.Clear()
cmd2.Connection = conn
'SELECT TOP 1 WITH TIES * FROM International ORDER BY News_ID DESC
cmd2.CommandText = "SELECT * FROM att_download where Machine_IP = '" & IP_txt.Text & "' and User_ID = '" & dr(0) & "' and Verify_Date = '" & Format(Convert.ToDateTime(dr(1)), ("yyyy-MM-dd")) & "' and Verify_Time = '" & Format(Convert.ToDateTime(dr(2)), "HH:mm:ss") & "' "
rd2 = cmd2.ExecuteReader
'SELECT ID FROM INVOICE_HEAD ORDER BY ID DESC LIMIT 1
If rd2.HasRows Then
rd2.Read()
'MessageBox.Show("موجود مسبقا" + " " + rd2.Item("User_ID").ToString)
rd2.Close()
Else
If dr(1) >= From_Date.EditValue And dr(1) <= To_Date.EditValue Then
Dim cmd4 As New SqlCommand
Dim rd4 As SqlDataReader
Dim ds4 As New DataSet
'Dim CustomerIDfromtheTbl
ds4.Clear()
cmd4.Connection = conn
'SELECT TOP 1 WITH TIES * FROM International ORDER BY News_ID DESC
cmd4.CommandText = "select * from Att_Users where user_code ='" & dr(0) & "' and machine_ip ='" & IP_txt.Text & "'"
rd4 = cmd4.ExecuteReader
'SELECT ID FROM INVOICE_HEAD ORDER BY ID DESC LIMIT 1
If rd4.HasRows Then
rd4.Read()
Dim sqlString As String = "insert into att_download (User_ID,Verify_Date,Verify_Time,Verify_Type,Verify_State,WorkCode,CREATE_USER,CREATE_DATE,CREATE_TIME,User_Name,Emp_Code,Machine_IP) " _
& "values (@User_ID,@Verify_Date,@Verify_Time,@Verify_Type,@Verify_State,@WorkCode,@CREATE_USER,@CREATE_DATE,@CREATE_TIME,@User_Name,@Emp_Code,@Machine_IP)"
Using cmd As SqlCommand = New SqlCommand(sqlString, conn)
cmd.Parameters.Add(New SqlParameter("@User_ID", dr(0)))
cmd.Parameters.Add(New SqlParameter("@Verify_Date", dr(1)))
cmd.Parameters.Add(New SqlParameter("@Verify_Time", dr(2)))
cmd.Parameters.Add(New SqlParameter("@Verify_Type", dr(3)))
cmd.Parameters.Add(New SqlParameter("@Verify_State", dr(4)))
cmd.Parameters.Add(New SqlParameter("@WorkCode", dr(5)))
cmd.Parameters.Add(New SqlParameter("@CREATE_USER", Main_UserName))
cmd.Parameters.Add(New SqlParameter("@CREATE_DATE", Format(Date.Today, ("yyyy-MM-dd"))))
cmd.Parameters.Add(New SqlParameter("@CREATE_TIME", Format(TimeOfDay, "hh:mm:ss")))
cmd.Parameters.Add(New SqlParameter("@User_Name", rd4.Item("user_name").ToString))
cmd.Parameters.Add(New SqlParameter("@Emp_Code", rd4.Item("Emp_Code").ToString))
cmd.Parameters.Add(New SqlParameter("@Machine_IP", IP_txt.Text))
cmd.ExecuteNonQuery()
End Using
rd4.Close()
End If
End If
End If
Next
此行生成错误：
else if (dr[1] >= From_Date.EditValue && dr[1] <= To_Date.EditValue)
XAML代码是：
<DataGrid x:Name="Logs_Grid" IsReadOnly="True" SelectionUnit="FullRow" AutoGenerateColumns="False" CanUserAddRows="True" Margin="138,179,10,10">
<DataGrid.Resources>
<Style BasedOn="{StaticResource {x:Type DataGridColumnHeader}}" TargetType="{x:Type DataGridColumnHeader}">
<Setter Property="Background" Value="#F78A09" />
<Setter Property="Foreground" Value="#F0F0F0" />
</Style>
<Style TargetType="ScrollBar" >
<Setter Property="Background" Value="#FAFAFA" />
</Style>
<Style TargetType="DataGridCell">
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="#360E05"/>
</Trigger>
</Style.Triggers>
</Style>
</DataGrid.Resources>
<DataGrid.Columns>
<DataGridTextColumn Header="كوده بالجهاز" x:Name="UserID" IsReadOnly="True" Binding="{Binding Path=UserID}" Foreground="#F0F0F0"/>
<DataGridTextColumn Header="تاريخ البصمة" x:Name="VerifyDate" IsReadOnly="True" Binding="{Binding Path=VerifyDate}" Foreground="#F0F0F0" />
<DataGridTextColumn Header="توقيت البصمة" x:Name="VerifyTime" IsReadOnly="True" Binding="{Binding Path=VerifyTime}" Foreground="#F0F0F0"/>
<DataGridTextColumn Header="نوع البصمة" x:Name="VerifyType" IsReadOnly="True" Binding="{Binding Path=VerifyType}" Foreground="#F0F0F0"/>
<DataGridTextColumn Header="حالة البصمة" x:Name="VerifyState" IsReadOnly="True" Binding="{Binding Path=VerifyState}" Foreground="#F0F0F0"/>
<DataGridTextColumn Header="كود العمل" x:Name="WorkCode" IsReadOnly="True" Binding="{Binding Path=WorkCode}" Foreground="#F0F0F0"/>
</DataGrid.Columns>
<DataGrid.RowStyle>
<Style TargetType="DataGridRow" >
<Setter Property="Background" Value="#8CB3EF"></Setter>
</Style>
</DataGrid.RowStyle>
</DataGrid>
<dxe:DateEdit x:Name="From_Date" HorizontalAlignment="Left" Margin="10,251,0,0" VerticalAlignment="Top" Width="120"/>
<dxe:DateEdit x:Name="To_Date" HorizontalAlignment="Left" Margin="10,314,0,0" VerticalAlignment="Top" Width="120"/>
答案 0 :(得分：1)
如果在VB中打开Option Strict，则会出现相同的错误。当Option Strict为Off时，VB尝试为您转换变量，而C＃则不这样做。您需要将变量转换为适当的数据类型。像这样：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<script src='https://www.google.com/recaptcha/api.js'></script>
</head>
<body>
<form action="formulario.php" method="post">
<input name="name" placeholder="Nombre"/>
<input name="email" placeholder="Email"/>
<div class="g-recaptcha" data-sitekey="MY-API-KEY"></div>
<button type="submit" name="submit">Enviar</button>
</form>
</body>
</html>
<?php
$name = stripslashes($_POST["name"]);
$email = stripslashes($_POST["email"]);
$recaptcha = $_POST["g-recaptcha-response"];
$url = 'https://www.google.com/recaptcha/api/siteverify';
$data = array(
'secret' => 'MY-SECRET-KEY',
'response' => $recaptcha,
‘remoteip’ => $_SERVER[‘HTTP_CLIENT_IP’]
);
$options = array(
'http' => array (
'method' => 'POST',
'content' => http_build_query($data)
)
);
$context = stream_context_create($options);
$verify = file_get_contents($url, false, $context);
$captcha_success = json_decode($verify);
if ($captcha_success->success) {
// No eres un robot, continuamos con el envío del email
// ...
// ...
echo "<h2>No eres un robot</h2>";
} else {
// Eres un robot!
echo "<h2>Eres un robot!</h2>";
}
?>
或使用该方法获取适当的变量
else if ((DateTime)dr[1] >= From_Date.EditValue && (DateTime)dr[1] <= To_Date.EditValue)