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DataSet Compute MAX Value

开发者 https://www.devze.com 2023-01-30 17:34 出处:网络
Disclaimer : I am new to C# and WPF and adding features to existing code. I am facing a problem while calculating the

Disclaimer : I am new to C# and WPF and adding features to existing code.

I am facing a problem while calculating the MAX value of db colums.

I have a Student database with table Sutent_DB

which has StudentID,StudentName,StudentClass I have to calculate the MAX of SudentID(ie:Number)

That I am doing it from DataSet.Table[Student_DB].Compute("MAX(StudentID)","") Which is returing a Number Object.(Working Fine)

Now I want to restrict my selection to only to selected StudentClass=5

ie : DataSet.Table[Student_DB].Select("StudentClass=5");

Here I am f开发者_StackOverflow中文版acing a problem to calculate the MAX(StudentID) as SELECT returns DATAROW

The solution in my find is

  int iMax=0;
  foreach ( DataRow oneNewrow DataSet.Table[Student_DB].Select("StudentClass=5"))
    {
       if iMax < oneNewrow["StudentID"]  

         iMax = oneNewrow["StudentID"]  ;

    }

///use iMax  here.

Just want to check any better or simple solution for my problem.


The second parameter of Compute is a filter:

int maxId = (int)DataSet.Table[Student_DB].Compute("MAX(StudentID)","StudentClass=5");


You can use Linq to Objects on the array of DataRows returned from your query. Here's an example:

int iMax = DataSet.Table[Student_DB].Select("StudentClass=5")).Max(row => row["StudentID"]);
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