未初始化SqlConnection的连接字符串属性

Question

我已经搜索过错误

  

连接字符串属性尚未初始化。

在谷歌以及Stack Overflow上但无法找到解决方案。我已经创建了一个用于与数据库交互的数据库类，所有相关代码都写在这个文件中。问题是相同的代码在其他页面上运行良好，它只是在名为“addevent.aspx”的页面上不起作用我不明白为什么它没有正常运行。

以下是我在database.cs文件中创建的方法

 SitePaymentReportByBranch = function () {
          $('#btnprintSitePaymentByBranch').on('click', function (e) {
              e.preventDefault();
              if ($("#form1").validationEngine('validate')) {
                  var _employerID = "";
                  if ($('#cmbEmployerSitPaymentByParameter :selected').text() == "-Select-") {
                      alert('Plz Select Employer');
                  }
                  var url = '/Reports/frmSitePayment.aspx?_EmployerID=' + $('#cmbEmployerSitPaymentByParameter :selected').val() + '&_Formdate=' + $("#formdate").val() + '&_Todate=' + $("#todate").val() +'_type=1';
                  commonStartup.openReportWindow(url);

              }
          });

      },

我根本不理解这个错误的逻辑及其发生。打开连接时出现此错误

如何调用这些方法，我已经在AddEvent方法之外创建了一个database.cs类的对象，对象名为mydb

public void CreateConnection()
{
    var ConfiguredString = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString;
    obj_sqlconnection = new SqlConnection(ConfiguredString);

}

//This property will set the connection string for database
public string ConnectionString
{
    get
    {   //if _connectionString is already created or set, only then it will return the value of _connectionString
        if (_connectionString != string.Empty && _connectionString != "" && _connectionString != null)
            return _connectionString;
        else
            return string.Empty;
    }
    // When you want to set the connection string set block is called.
    set
    {   // this line sets the connection string to the _connectionString data member for the first time.
        if (_connectionString == string.Empty || _connectionString == "" || _connectionString == null)
            _connectionString = value;
    }
}

// Open database connection.    
public void OpenConnection()
{
    obj_sqlconnection.Open();
}

// Close database connection.
public void CloseConnection()
{
    obj_sqlconnection.Close();
    obj_sqlconnection.Dispose();
}

public SqlConnection GetCurrentConnection
{
    get { return obj_sqlconnection; }
    set { obj_sqlconnection = value; }
}

Answer 1

这是太复杂的解决方案......这将解决您的理解问题和不必要的代码行：

溶液：

namespace Stackoverflow
{
    public static class Solution
    {
        static readonly string _connectionStringName =
            @"mainConnectionStringName";

        static readonly string _connectionString =
            _connectionStringName.getConnectionString();

        // string extended method like .ToLower() or .Trim()
        public static string getConnectionString(
            this string connectionStringName)
        {
            return
                System.
                Configuration.
                ConfigurationManager.
                ConnectionStrings[connectionStringName].
                ConnectionString;
        }

        public static object SqlExecute(
            string connectionStringName,
            string storedProcedureName,
            System
                .Collections
                .Generic
                .Dictionary<string, object> parameters,
            bool isScalar)
        {
            object result = null;

            using (System
                      .Data
                      .SqlClient
                      .SqlConnection connection =
                new System.Data.SqlClient.SqlConnection(
                    string.IsNullOrWhiteSpace(connectionStringName)
                        ? _connectionString
                        : connectionStringName.getConnectionString()))
                if (connection != null)
                    using (System.Data.SqlClient.SqlCommand command =
                        new System.Data.SqlClient.SqlCommand()
                        {
                            CommandText = storedProcedureName,
                            CommandType = System
                                             .Data
                                             .CommandType
                                             .StoredProcedure,
                            Connection = connection
                        })
                        if (command != null)
                        {
                            if (parameters != null)
                                foreach (System
                                            .Collections
                                            .Generic
                                            .KeyValuePair<string, object>
                                                pair in parameters)
                                    command.Parameters.AddWithValue(
                                        pair.Key, pair.Value);

                            command.Connection.Open();

                            result = isScalar
                                ? command.ExecuteScalar()
                                : command.ExecuteNonQuery();

                            if (command.Connection.State ==
                                    System.Data.ConnectionState.Open)
                                command.Connection.Close();
                        }

            return result;
        }
    }
}

用法：

namespace SomeNamespace
{
    public sealed class SomeClass
    {
        public int Example()
        {
            return (int)Stackoverflow
                .Solution
                .SqlExecute(
                    @"anyConnectionStringName", // or null for main connection string
                    @"anyStoredProcedureName",
                    new System
                        .Collections
                        .Generic
                        .Dictionary<string, object>()
                    {
                        { @"field0", "value" },
                        { @"field1", -1.5 },
                        { @"field2", System.DateTime.Now },
                        { @"field3", 3.5 },
                        { @"field4", 7 },
                    },
                    false // for ExecuteNonQuery or true for ExecuteScalar
                );
        }
    }
}