从C＃中的结构构建逗号分隔的字符串

Question

I have the following struct in C# class

public struct Employee
        {
            public const string EMPID = "EMP_ID";
            public const string FName = "FIRST_NAME";
            public const string LNAME = "LAST_NAME";
            public const string DEPTID = "DEPT_ID";

        }

Is there an easy way to build a string as follows

const string mainquery="INSERT INTO EMP(EMP_ID,FIRST_NAME,LAST_NAME,DEPT_ID) VALUES(:EMP_ID,:FIRST_NAME,:LAST_NAME,:DEPT_ID)"

Instead of doing as follows and then concatenating it.

const string EMP_COLS=
                EMPLOYEE.EMPID + "," +
                EMPLOYEE.FNAME + "," +
        EMPLOYEE.LNAME + "," +
                EMPLOYEE.DEPTID;

            const string EMP_Values=
                EMPLOYEE.EMPID + ":" +
                EMPLOYEE.FNAME + ":" +
        EMPLOYEE.LNAME + ":" +
                EMPLOYEE.DEPTID;

Answer 1

You could try something like this:

StringBuilder sb = new StringBuilder();
var fields = typeof(Employee).GetFields();
for (int i = 0; i < fields.Length; ++i)
{
    sb.Append(fields[i].GetValue(new Employee()));
    if (i < fields.Length - 1)
    {
        sb.Append(',');
    }
}

string result = sb.ToString();
// The above will be "EMP_ID,FIRST_NAME,LAST_NAME,DEPT_ID"

Edit : Note that above I'm assuming you've got using directives for both System.Reflection and System.Text .

Answer 2

If the struct held readonly properties rather than public consts you could do it with Reflection. You could call Type.GetProperties , loop through them all and call them to get out the values and insert the values into a List<string> and then join them with string.Join(", ", myList); or something.
You'd then get the first part of the string as EMP_ID, FIRST_NAME, LAST_NAME, DEPT_ID and you'd need to make a copy of that and add the : s as needed and you'd have both parts.

Answer 3

you can use the string.Format(string format, object[] arg) Method as follows:

string query = string.Format("INSERT INTO EMP({0},{1},{2},{3}) VALUES(:{0},:{1},:{2},:{3})",
                Employee.EMPID,
                Employee.FNAME,
                Employee.LNAME,
                Employee.DEPTID);

Hope that helps.

Answer 4

您将需要某种映射字典，例如here ，或者您可以使用某种ORM工具为您完成映射。

Answer 5

        string[] values = new[] {
            "EMP_ID",
            "FIRST_NAME",
            "LAST_NAME",
            "DEPT_ID",
        };

        var columns = string.Join(",", values);
        var parameters = ":" + string.Join(",:", values);

        var sql = string.Format("INSERT INTO EMP({0}) VALUES({1})",
            columns,
            parameters);

Answer 6

string[] cols = typeof(Employee).GetFields()
                 .Select(f => f.GetValue(null).ToString()).ToArray();

Console.WriteLine(string.Format(
      "INSERT INTO EMP({0}) VALUES(:{1})", 
      string.Join(",", cols), 
      string.Join(",:", cols)));