how to get the stored procedure script in the C#

Run the following two queries from C# you will get the desired result
run the following script you will get the definition of st pro

SELECT definition FROM sys.sql_modules 
WHERE [object_id] = OBJECT_ID('dbo.procedurename');

and you can get the params by running this query

SELECT name, system_type_id, max_length, precision, scale
FROM sys.parameters
WHERE [object_id] = OBJECT_ID('dbo.procedurename');

private string AddColumnInStoredProcedure(String newColumn)
{
try
{
connStringForDB = ConfigurationManager.ConnectionStrings["Conv3DBConnectionString"].ConnectionString;
sqlconn = new SqlConnection(connStringForDB);
if (sqlconn.State == 0)
sqlconn.Open();
string strSQL = "SELECT text FROM syscomments WHERE id = (SELECT id FROM sysobjects WHERE name = 'InsertRequestForexcel_temp_sp') ORDER BY colid";
DataSet ds = new DataSet();
sqlconn.Open();
SqlDataAdapter da = new SqlDataAdapter(strSQL, sqlconn);
//sqlconn.Close();
da.Fill(ds);
StringBuilder sb = new StringBuilder();
foreach (DataRow item in ds.Tables[0].Rows)
{
string Str = item.ItemArray[0].ToString();
string strNew = string.Empty;
string newColumn = "newCOl";
if (Str.Contains("--(EOP)"))
{
int startIndex = Str.IndexOf("--(EOP)");
strNew = Str.Substring(0, startIndex) + "@" + newColumn + " varchar(10), " + Str.Substring(startIndex);
}
if (Str.Contains("--(ICN)") && strNew == string.Empty)
{
int startIndex = Str.IndexOf("--(ICN)");
strNew = Str.Substring(0, startIndex) + "," + newColumn + " " + Str.Substring(startIndex);//INSERT COLUMN NAME
}
else if (strNew.Contains("--(ICN)") && strNew != string.Empty)
{
int startIndex = strNew.IndexOf("--(ICN)");
strNew = strNew.Substring(0, startIndex) + "," + newColumn + " " + strNew.Substring(startIndex);//INSERT COLUMN NAME
}
if (Str.Contains("--(ICV)") && strNew == string.Empty)
{
int startIndex = Str.IndexOf("--(ICV)");
strNew = Str.Substring(0, startIndex) + ",@" + newColumn + " " + Str.Substring(startIndex);//INSERT COLUMN VALUE(PARAMETER NAME)
}
else if (strNew.Contains("--(ICV)") && strNew != string.Empty)
{
int startIndex = strNew.IndexOf("--(ICV)");
strNew = strNew.Substring(0, startIndex) + ",@" + newColumn + " " + strNew.Substring(startIndex);//INSERT COLUMN NAME
}
if (strNew != "")
{
sb.Append(strNew);
//strList.Add(strNew);
}
else
{
sb.Append(Str);
//strList.Add(Str);
}


}

//SqlCommand cmd = new SqlCommand(sb.ToString(),sqlconn);
SqlCommand cmd = new SqlCommand("Alter " + sb.ToString().Substring(6), sqlconn);
cmd.ExecuteNonQuery();



}