无法保存数据c# Windows应用程序。

here is my code

这是我的代码

 private void button1_Click(object sender, EventArgs e)
    {
        try
        {
            string connectionString = @"Data Source=|DataDirectory|\Database_POS.sdf";
            using (SqlConnection connection = new SqlConnection(connectionString))
            using (SqlCommand command = connection.CreateCommand())
            {
                command.CommandText= "INSERT INTO Customer (Email) Values (@email);";
                command.Parameters.AddWithValue("@email",textBox_Email.Text);

                connection.Open();
                command.ExecuteNonQuery(); 
            }
        }

        catch (SqlException ex)
        {
            Console.WriteLine(ex.Message);
        }
    }  

here is my design

这是我的设计

    I am only trying to save 'email' here. 

Here is my sql table, problem is I can not even save a single field into table .

这是我的sql表，问题是我甚至不能将一个字段保存到表中。

Database Design

数据库设计

Now error is this

这是现在的错误

2 个解决方案

#1

Some things to check:

有些东西检查:

1. Do you event get an error? If yes, what is the error? Be aware that you are writing the error message to the Console window, but your application is a Windows Application. Does your application have a Console window? If no, check the Output window in Visual Studio. Or simpler yet, use MessageBox.Show to show the error.

   你的事件有错误吗?如果是，错误是什么?请注意，您正在将错误消息写入控制台窗口，但是您的应用程序是Windows应用程序。你的应用程序有控制台窗口吗?如果没有，请检查Visual Studio中的输出窗口。或者更简单，使用MessageBox。显示错误。

2. If program runs without any error, check the return value of command.ExecuteNonQuery(). It tells you how many records affected. If it is more that zero, the value is really being stored in the database.

   如果程序运行无误，请检查command.ExecuteNonQuery()的返回值。它告诉你有多少条记录受到影响。如果值大于0，则该值实际上存储在数据库中。

3. Make sure that you are seeing the contents of the database file that you are inserting to in your program! You may have opened Database_POS.sdf from your project directory, but the program inserts the data into another Database_POS.sdf in your "bin\Debug" directory.

   确保您正在查看您在程序中插入的数据库文件的内容!您可能已经打开了Database_POS。来自项目目录的sdf，但是程序将数据插入另一个Database_POS。在“bin\Debug”目录下的sdf。

-- More Help --

——更多的帮助

Change your method to:

改变你的方法:

private void button1_Click(object sender, EventArgs e)
{
    try
    {
        string connectionString = @"Data Source=|DataDirectory|\Database_POS.sdf";
        using (SqlConnection connection = new SqlConnection(connectionString))
        using (SqlCommand command = connection.CreateCommand())
        {
            command.CommandText= "INSERT INTO Customer (Email) Values (@email);";
            command.Parameters.AddWithValue("@email",textBox_Email.Text);

            connection.Open();
            var rowsAffected = command.ExecuteNonQuery();
            if(rowsAffected > 0)
                MessageBox.Show("Data inserted successfully");
            else
                MessageBox.Show("Nothing inserted into the database!");
        }
    }

    catch (SqlException ex)
    {
        Console.WriteLine(ex.Message);
        MessageBox.Show(ex.ToString()); // for debugging purpose
    }
}

#2

thanks everyone for answers

感谢每个人的答案

Cannot connect to local database in C#

无法连接到c#中的本地数据库

I got my answer form above link.

我的答案在链接上面。

I am using Compact Database and Trying to connect like SQLServer.

我正在使用紧凑数据库并尝试像SQLServer那样连接。

Now got it working.

现在找到了工作。

here is the answer text ,that solve my question

这是答案，可以解决我的问题

When using a .sdf file (SQL Server Compact Edition), you need to use SqlCeConnection and not SqlConnection (that works against a full SQL Server):