使用SqlParameter的SELECT查询不工作

我不确定你的InsertRecord方法在做什么，但你正在传递原始字符串insertCustomerString给它，而不是你的SqlCommand对象。字符串不知道你对参数做了什么，所以如果InsertRecord期望字符串知道参数的值，它会失望的。

方法如下:
此外，不应该使用原始的System.Data.SqlClient对象，而应该使用常见的接口类型。

 System.Data.IDbConnection idbc = new System.Data.SqlClient.SqlConnection("connectionstring");
    System.Data.IDbCommand cmd = idbc.CreateCommand();
    cmd.CommandText = "INSERT INTO Customer1 (FirstName, LastName, Address, City, State, Zip, Phone, Notes) Values (@p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8)";
    System.Data.IDbDataParameter parm = cmd.CreateParameter();
    parm.DbType = System.Data.DbType.AnsiString;
    parm.ParameterName = "@p1";
    parm.Value = "ValueOfP1";
    cmd.Parameters.Add(parm);
    // etc.
    if(cmd.Connection.State != System.Data.ConnectionState.Open)
        cmd.Connection.Open();
    cmd.ExecuteNonQuery();
    if (cmd.Connection.State != System.Data.ConnectionState.Closed)
        cmd.Connection.Close();

同时，你应该对所有的value对象使用using和lock;)

    using (System.Data.IDbConnection idbc = new System.Data.SqlClient.SqlConnection("connectionstring"))
    {
        lock (idbc)
        {
            using (System.Data.IDbCommand cmd = idbc.CreateCommand())
            {
                lock (cmd)
                {
                    cmd.CommandText = "INSERT INTO Customer1 (FirstName, LastName, Address, City, State, Zip, Phone, Notes) Values (@p1, @p2, @p3, @p4, @p5, @p6, @p7, @p8)";
                    System.Data.IDbDataParameter parm = cmd.CreateParameter();
                    parm.DbType = System.Data.DbType.AnsiString;
                    parm.ParameterName = "@p1";
                    parm.Value = "ValueOfP1";
                    cmd.Parameters.Add(parm);
                    //
                    if (cmd.Connection.State != System.Data.ConnectionState.Open)
                        cmd.Connection.Open();
                    cmd.ExecuteNonQuery();
                    if (cmd.Connection.State != System.Data.ConnectionState.Closed)
                        cmd.Connection.Close();
                }
            }
        }
    }

作为额外的备注，你不应该使用新的System.Data.SqlClient.SqlConnection，相反，您应该使用工厂类型，如:

System.Data.Common.DbProviderFactory fac = System.Data.Common.DbProviderFactories.GetFactory("System.Data.SqlClient");
            System.Data.IDbConnection idbc = fac.CreateConnection();
            idbc.ConnectionString = "ConnectionString";

还可以自动将值映射到相应的sql类型:

// From Type to DBType
protected virtual System.Data.DbType GetDbType(Type type)
{
    // http://social.msdn.microsoft.com/Forums/en/winforms/thread/c6f3ab91-2198-402a-9a18-66ce442333a6
    string strTypeName = type.Name;
    System.Data.DbType DBtype = System.Data.DbType.String; // default value
    try
    {
        if (object.ReferenceEquals(type, typeof(System.DBNull)))
        {
            return DBtype;
        }
        if (object.ReferenceEquals(type, typeof(System.Byte[])))
        {
            return System.Data.DbType.Binary;
        }
        DBtype = (System.Data.DbType)Enum.Parse(typeof(System.Data.DbType), strTypeName, true);
        // Es ist keine Zuordnung von DbType UInt64 zu einem bekannten SqlDbType vorhanden.
        // http://msdn.microsoft.com/en-us/library/bbw6zyha(v=vs.71).aspx
        if (DBtype == System.Data.DbType.UInt64)
            DBtype = System.Data.DbType.Int64;
    }
    catch (Exception)
    {
        // add error handling to suit your taste
    }
    return DBtype;
} // End Function GetDbType

public virtual System.Data.IDbDataParameter AddParameter(System.Data.IDbCommand command, string strParameterName, object objValue)
{
    return AddParameter(command, strParameterName, objValue, System.Data.ParameterDirection.Input);
} // End Function AddParameter

public virtual System.Data.IDbDataParameter AddParameter(System.Data.IDbCommand command, string strParameterName, object objValue, System.Data.ParameterDirection pad)
{
    if (objValue == null)
    {
        //throw new ArgumentNullException("objValue");
        objValue = System.DBNull.Value;
    } // End if (objValue == null)
    System.Type tDataType = objValue.GetType();
    System.Data.DbType dbType = GetDbType(tDataType);
    return AddParameter(command, strParameterName, objValue, pad, dbType);
} // End Function AddParameter

public virtual System.Data.IDbDataParameter AddParameter(System.Data.IDbCommand command, string strParameterName, object objValue, System.Data.ParameterDirection pad, System.Data.DbType dbType)
{
    System.Data.IDbDataParameter parameter = command.CreateParameter();
    if (!strParameterName.StartsWith("@"))
    {
        strParameterName = "@" + strParameterName;
    } // End if (!strParameterName.StartsWith("@"))
    parameter.ParameterName = strParameterName;
    parameter.DbType = dbType;
    parameter.Direction = pad;
    // Es ist keine Zuordnung von DbType UInt64 zu einem bekannten SqlDbType vorhanden.
    // No association  DbType UInt64 to a known SqlDbType
    if (objValue == null)
        parameter.Value = System.DBNull.Value;
    else
        parameter.Value = objValue;
    command.Parameters.Add(parameter);
    return parameter;
} // End Function AddParameter

public virtual T GetParameterValue<T>(System.Data.IDbCommand idbc, string strParameterName)
{
    if (!strParameterName.StartsWith("@"))
    {
        strParameterName = "@" + strParameterName;
    }
    return InlineTypeAssignHelper<T>(((System.Data.IDbDataParameter)idbc.Parameters[strParameterName]).Value);
} // End Function GetParameterValue<T>

如果你这样做，你保持与所有ado.net数据库提供程序的可移植性，并且只需要在改变数据库类型时适应getfactory中的字符串和sql代码。