'ConnectionString 属性尚未初始化。'修理答案

【问题标题】：'The ConnectionString property has not been initialized.' TO FIX'ConnectionString 属性尚未初始化。'修理
【发布时间】：2018-03-07 10:07:46
【问题描述】：

我目前收到错误： System.InvalidOperationException：“ConnectionString 属性尚未初始化。” 我想要一些帮助来解决这个问题，因为我正在尝试将数据从 c#form（多个文本框）输入到我当前代码的 SQL 数据库表单

 private void AcceptData()
    {
        using (Connection = new SqlConnection(connectionString))
        using (SqlDataAdapter adapter = new SqlDataAdapter("INPUT INTO Person", Connection))//, Connection
        {
            DataTable RegisterTable = new DataTable();
            adapter.Fill(RegisterTable); //System.InvalidOperationException: 'The ConnectionString property has not been initialized.' TO FIX

            string name = textBox1.Text;
            string organisation = textBox3.Text;
            DateTime Time = DateTime.Parse(textBox2.Text);
            string strDateTimeIn = Time.ToString("yyyy-MM-dd HH:mm:ss.ffff");
            string query = "INSERT INTO Person (Name,Organisation,TimeIn) VALUES('" + name + "','" + organisation + "','" +strDateTimeIn+ "')";
            SqlCommand SignIn = new SqlCommand(query,Connection);
            SignIn.ExecuteNonQuery();
        }

    }

任何帮助将不胜感激，谢谢

使用的连接字符串是：string connectionString = (@"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Register.mdf;Integrated Security=True");

【问题讨论】：

@Corak 可能是因为它是 LocalDB（例如like this）
@DavidG - 啊，谢谢！

标签： c# sql

【解决方案1】：

你需要打开连接

using (Connection = new SqlConnection(connectionString))
{
    connection.Open();

    using (SqlDataAdapter adapter = new SqlDataAdapter("INPUT INTO Person", Connection))//, Connection
        {
            DataTable RegisterTable = new DataTable();
            adapter.Fill(RegisterTable); //System.InvalidOperationException: 'The ConnectionString property has not been initialized.' TO FIX

            string name = textBox1.Text;
            string organisation = textBox3.Text;
            DateTime Time = DateTime.Parse(textBox2.Text);
            string strDateTimeIn = Time.ToString("yyyy-MM-dd HH:mm:ss.ffff");
            string query = "INSERT INTO Person (Name,Organisation,TimeIn) VALUES('" + name + "','" + organisation + "','" +strDateTimeIn+ "')";
            SqlCommand SignIn = new SqlCommand(query,Connection);
            SignIn.ExecuteNonQuery();
        }
}

【讨论】：

【解决方案2】：

“ConnectionString 属性尚未初始化” 清楚地表明用于打开SqlConnection 的连接字符串属性在方法内部未正确分配。要解决此问题，请在方法主体中分配连接字符串，如下所示：

private void AcceptData()
{
    // assumed the connection string obtained from app.config or web.config file
    string connectionString = ConfigurationManager.ConnectionStrings["ConnectionStringName"].ConnectionString;
    using (SqlConnection Connection = new SqlConnection(connectionString))
    {
        Connection.Open(); // open the connection before using adapter
        using (SqlDataAdapter adapter = new SqlDataAdapter("INPUT INTO Person", Connection))
        {
            // other stuff
        }
    }

    // other stuff
}

或者将连接字符串作为方法参数传递：

private void AcceptData(string connectionString)
{
    using (SqlConnection Connection = new SqlConnection(connectionString))
    {
        Connection.Open(); // open the connection before using adapter
        using (SqlDataAdapter adapter = new SqlDataAdapter("INPUT INTO Person", Connection))
        {
            // other stuff
        }
    }

    // other stuff
}

参考资料：

How to fix "The ConnectionString property has not been initialized"

C# Database The ConnectionString property has not been initialized

【讨论】：