BaseClass”的类型初始值设定项引发异常。请问如何处理

qq_37052663 2017-01-03 10:13:47

public class BaseClass
{

public static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
public static int ExecuteNonQuery(string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
cmd.CommandTimeout = 60;
using (SqlConnection conn = new SqlConnection(ConnectionString))
{
PrepareCommand(cmd, conn, null, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}
/// <summary>
/// 用现有的数据库连接执行一个sql命令（不返回数据集）
/// </summary>
/// <remarks>
///举例:
/// int result = ExecuteNonQuery(connString, "PublishOrders", new OleDbParameter("@prodid", 24));
/// </remarks>
/// <param name="conn">一个现有的数据库连接</param>
/// <param name="commandText">存储过程名称或者sql命令语句</param>
/// <param name="commandParameters">执行命令所用参数的集合</param>
/// <returns>执行命令所影响的行数</returns>
public static int ExecuteNonQuery(SqlConnection connection, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, connection, null, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/// <summary>
///使用现有的SQL事务执行一个sql命令（不返回数据集）
/// </summary>
/// <remarks>
///举例:
/// int result = ExecuteNonQuery(trans, "PublishOrders", new OleDbParameter("@prodid", 24));
/// </remarks>
/// <param name="trans">一个现有的事务</param>
/// <param name="commandText">存储过程名称或者sql命令语句</param>
/// <param name="commandParameters">执行命令所用参数的集合</param>
/// <returns>执行命令所影响的行数</returns>
public static int ExecuteNonQuery(SqlTransaction trans, string cmdText, params SqlParameter[] commandParameters)
{
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
/// <summary>
/// 用执行的数据库连接执行一个返回数据集的sql命令
/// </summary>
/// <remarks>
/// 举例:
/// OleDbDataReader r = ExecuteReader(connString, "PublishOrders", new OleDbParameter("@prodid", 24));
/// </remarks>
/// <param name="connectionString">一个有效的连接字符串</param>
/// <param name="commandText">存储过程名称或者sql命令语句</param>
/// <param name="commandParameters">执行命令所用参数的集合</param>
/// <returns>包含结果的读取器</returns>
public static SqlDataReader ExecuteReader(string cmdText, params SqlParameter[] commandParameters)
{
//创建一个SqlCommand对象
SqlCommand cmd = new SqlCommand();
//创建一个SqlConnection对象
SqlConnection conn = new SqlConnection(ConnectionString);
//在这里我们用一个try/catch结构执行sql文本命令/存储过程，因为如果这个方法产生一个异常我们要关闭连接，因为没有读取器存在，
//因此commandBehaviour.CloseConnection 就不会执行
try
{
//调用 PrepareCommand 方法，对 SqlCommand 对象设置参数
PrepareCommand(cmd, conn, null, cmdText, commandParameters);
//调用 SqlCommand 的 ExecuteReader 方法
SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
//清除参数
cmd.Parameters.Clear();
return reader;
}
catch
{
//关闭连接，抛出异常
conn.Close();
throw;
}
}

public string addmenu()
{
string sql = "select * from menu_2017";
string shtml = "";

SqlDataReader DataRead =BaseClass.ExecuteReader(sql,null);
while (DataRead.Read())
{
shtml = shtml + DataRead["syspagename"].ToString();

执行到 SqlDataReader DataRead =BaseClass.ExecuteReader(sql,null);就报错，提示：
BaseClass”的类型初始值设定项引发异常。

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