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我有一个无法重用的丑陋代码。我有很多类似的疑问。我想用 SqlParameterCollectionExtensions 或其他更好的方法重写它。但我根本不知道 SqlParameterCollectionExtensions。

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        SqlConnection con = new SqlConnection(strCon);
        con.Open();
        SqlCommand cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandText = "UPDATE Problem_DE SET ProbDesc = @ProbDesc, field_1 = @field_1, field_2 = @field_2, field_3 = @field_3, field_4 = @field_4, field_5 = @field_5, field_6 = @field_6, field_7 = @field_7 WHERE (ProbId = @ProbId)";
        if (e.NewValues["ProbDesc"] == null)
            cmd.Parameters.AddWithValue("@ProbDesc", DBNull.Value);
        else
            cmd.Parameters.AddWithValue("@ProbDesc", e.NewValues["ProbDesc"]);
        if (e.NewValues["field_1"] == null)
            cmd.Parameters.AddWithValue("@field_1", DBNull.Value);
        else
            cmd.Parameters.AddWithValue("@field_1", e.NewValues["field_1"]);
        if (e.NewValues["field_2"] == null)
            cmd.Parameters.AddWithValue("@field_2", DBNull.Value);
        else
            cmd.Parameters.AddWithValue("@field_2", e.NewValues["field_2"]);
        if (e.NewValues["field_3"] == null)
            cmd.Parameters.AddWithValue("@field_3", DBNull.Value);
        else
            cmd.Parameters.AddWithValue("@field_3", e.NewValues["field_3"]);

        if (e.NewValues["field_4"] == null)
            cmd.Parameters.AddWithValue("@field_4", DBNull.Value);
        else
            cmd.Parameters.AddWithValue("@field_4", e.NewValues["field_4"]);
         \\ blah blah
        cmd.ExecuteNonQuery();
        con.Close();
     }

sql参数来自e或文本框等。谢谢。

4

2 回答 2

1

也许是这样的？我假设问题是您有可变数量的值，具体取决于问题表？

private void UpdateProblem(string problemName, string problemDescription, int problemId, object[] fieldValues)
{
    SqlConnection   con = null;
    SqlCommand      cmd = new SqlCommand();
    StringBuilder   sql = new StringBuilder();
    int             fieldCounter = 1;

    // start building the sql statement
    sql.AppendFormat("UPDATE {0} SET ProbDesc = @ProbDesc", problemName);

    // add the 'description' parameter
    cmd.Parameters.Add(new SqlParameter("@ProbDesc", problemDescription));

    // add each field value to the update statement... the SqlParameter will infer the database type.
    foreach(object fieldValue in fieldValues)
    {
        // add additional SET clauses to the statement
        sql.AppendFormat(",field{0} = @field{0}", fieldCounter);

        // add the field parameter to the command's collection
        cmd.Parameters.Add(new SqlParameter(String.Format("@field{0}", fieldCounter), fieldValue));

        fieldCounter++;
    }

    // finish up the SQL statement by adding the where clause
    sql.Append(" WHERE (ProbId = @ProbId)");

    // add the 'problem ID' parameter to the command's collection
    cmd.Parameters.Add(new SqlParameter("@ProbId", problemId));

    // finally, execute the SQL
    try
    {
        con.Open();

        cmd.Connection = con;

        cmd.CommandText = sql.ToString();

        cmd.ExecuteNonQuery();
    }
    catch(SqlException ex)
    {
        // do some exception handling
    }
    finally
    {
        if(con != null)
            con.Dispose();
    }
}

调用此代码的示例是：

public void UpdateProblemDe()
{
    int         problemId = FetchCurrentProblemId();
    string      field1 = e.NewValues["field_1"];
    string      field2 = e.NewValues["field_2"];
    string      field3 = ddlField3.SelectedValue;
    int         field4 = Convert.ToInt32(e.NewValues["field_4"]);
    string      field5 = txtField5.Text;
    DateTime    field6 = DateTime.Now.AddSeconds(Convert.ToInt32(ddlField6.SelectedValue));
    string      field7 = txtField7.Text;
    object[6]   fieldValues;

    if(field1 != null)
        fieldValues[0] = field1;
    else
        fieldValues[0] = DBNull.Value;

    if(field2 != null)
        fieldValues[1] = field2;
    else
        fieldValues[1] = DBNull.Value

    fieldValues[2] = field3;
    fieldValues[3] = field4;    
    fieldValues[4] = field5;
    fieldValues[5] = field6;
    fieldValues[6] = field7;

    UpdateProblem("Problem_DE", "Houston, we have a problem", problemId, fieldValues);  
}

上面的示例代码显然只是演示如何从页面控件值存储对象数组，并且不包括您需要在生产代码中实现的任何数据验证。

如果您不知道 object[] 数组在运行时需要多大，您可以将其更改为通用对象列表并动态添加项目。

于 2012-04-12T00:55:45.860 回答
0

基于此答案 创建新的 SQLCommand 或重用相同的 SQLCommand， 您可以通过以下方式重构代码

public class DbHepler
    {
        private readonly string _connectionString;
        public DbHepler(string connectionString)
        {
            _connectionString = connectionString;
        }

        public void ExecuteNonQuery(string query)
        {
            ExecuteNonQuery(query, null);
        }

        public void ExecuteNonQuery(string query, Dictionary<string, object> parameters)
        {
            using (SqlConnection conn = new SqlConnection(_connectionString))
            {
                conn.Open();

                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = query;

                    if (parameters != null)
                    {
                        foreach (string parameter in parameters.Keys)
                        {
                            cmd.Parameters.AddWithValue(parameter, parameters[parameter] ?? DBNull.Value);
                        }
                    }

                    cmd.ExecuteNonQuery();
                }

                conn.Close();
            }
        }
    }

您的代码将类似于：

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            string query = "UPDATE Problem_DE SET ProbDesc = @ProbDesc, field_1 = @field_1, field_2 = @field_2, field_3 = @field_3, field_4 = @field_4, field_5 = @field_5, field_6 = @field_6, field_7 = @field_7 WHERE (ProbId = @ProbId)";
            Dictionary<string, object> parameters = new Dictionary<string, object>();

            if (e.NewValues["ProbDesc"] == null)
                parameters.Add("@ProbDesc", null);
            else
                parameters.Add("@ProbDesc", e.NewValues["ProbDesc"]);

            //blah blah

            DbHepler dbHepler = new DbHepler("your sql connection info");
            dbHepler.ExecuteNonQuery(query, parameters);
         }
于 2012-04-12T00:56:16.217 回答