CODEWITHSUNDEEP
c#sqlsql-serversql-server-2008
B.M.A
B.M.A

Reputation: 175

How can I resolve this error an c#

I want to insert data into a database table:

myCommand.CommandText = "INSERT INTO Selectionner (IdPrestation,
   IdPhrase, DegreUrgence,RisqueConcerne,rowguid,Cotation) " +                                                               
   "VALUES   ('" +new Guid(emp.IdPrestation) + 
   "', '" +new Guid(emp.IdPhrase)+ "', '" +
   emp.DegreUrgence + "','" + emp.RisqueConcerne + "','" + 
   new Guid(emp.rowguid) + "','" + emp.Cotation + "')";

But this returns an error:

Guid should contain 32 digits with 4 dashes
(xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).

How can I resolve this error ?

Upvotes: 1

Views: 1207

Answers (3)

Kaf
Kaf

Reputation: 33809

One or many of your

emp.IdPrestation //Or 
emp.IdPhrase //Or 
emp.rowguid //Check them before creating

is/are not a GUID. That is why it is throwing an error.

EDIT: starts

How to use Guid.TryParse() which returns true if the parse operation was successful; otherwise, false. 

//How to parse safely
Guid IdPrestation;
Guid IdPhrase;
Guid rowguid;

if(Guid.TryParse(emp.IdPrestation, out IdPrestation) &&
   Guid.TryParse(emp.IdPhrase, out IdPhrase) &&
   Guid.TryParse(emp.rowguid, out rowguid) )
{
   //all variables have been parse successfully
   //Execute the sql query as follows using parameters
}

EDIT: ends

Also, passing parameters as direct string with inline sql is an unsafe bad practice. Instead use a parameterised query.

myCommand.CommandText = "INSERT INTO yourTableName (c1, c2, ...)
VALUES (@p1, @p2,...)";
myCommand.Parameters.Add(new SqlParameter("p1", valueforCol1));
myCommand.Parameters.Add(new SqlParameter("p2", valueforCol2));
...

Upvotes: 6

sajanyamaha
sajanyamaha

Reputation: 3198

You cannot create GUID simply from a string ,the string needs to be guid compliant

Guid originalGuid = Guid.NewGuid();
originalGuid.ToString("B")  gets converted to {81a130d2-502f-4cf1-a376-63edeb000e9f}

Similarly

"N" - xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx (32 digits)
"D" - xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx (32 digits separated by hyphens)
"B" - {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} (same as "D" with addition of braces)
"P" - (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx) (same as "D" with addition of parentheses)
"X" - {0x00000000,0x0000,0x0000,{0x00,0x00,0x00,0x00,0x00,0x00,0x00.0x00}}

The guid itself has no format. It is just a value. Note, that you can create guids using NewGuid or using the guid's constructor. Using NewGuid, you have no control over the value of the guid. Using the guid's constructor, you can control the value. Using the constructor is useful if you already have a string representation of a guid (maybe you read it from a database) or if you want to make it easier to interpret a guid during development. You can also use the Parse, ParseExact, TryParse, and TryParseExact methods.

So, you can create guids like this:

Guid g1 = Guid.NewGuid(); //Get a Guid without any control over the contents
Guid g2 = new Guid(new string('A',32)); //Get a Guid where all digits == 'A'
Guid g3 = Guid.Parse(g1.ToString());
Guid g4 = Guid.ParseExact(g1.ToString("D"),"D");
Guid g5;
bool b1 = Guid.TryParse(g1.ToString(), out g5);
Guid g6;
bool b2 = Guid.TryParseExact(g1.ToString("D"),"D", out g6);

Upvotes: 1

dutzu
dutzu

Reputation: 3910

Try to use a parameterised query as a first improvement.

Then, try to use Guid.Parse(string s) instead of new Guid(string s). That way, i expect that an exception will be raised for the strings that are not compliant.

The constructor might be a little to permissive, and in this case you would want to fail-fast so that you know what field is giving you trouble.

Upvotes: 4

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