How to Get a Specific Column Value from a DataTable

Question

I have a datatable  I need to fetch a certain column value based on the user input  For example  lets say the datatable has two columns CountryID and CountryName   I need to find CountryID in the datatable based on the user input country name  I could just open a connection with DB and run the query select countryID from Country where countryName    userinput  Is there anyway i could do this on the datatable

User · Answer

I suppose you could use a DataView object instead, this would then allow you to take advantage of the RowFilter property as explained here:

http://msdn.microsoft.com/en-us/library/system.data.dataview.rowfilter.aspx

private void MakeDataView() 
{
    DataView view = new DataView();

    view.Table = DataSet1.Tables["Countries"];
    view.RowFilter = "CountryName = 'France'";
    view.RowStateFilter = DataViewRowState.ModifiedCurrent;

    // Simple-bind to a TextBox control
    Text1.DataBindings.Add("Text", view, "CountryID");
}

User · Answer

string countryName    USA   DataTable dt   new DataTable    int id    from DataRow dr in dt Rows               where  string dr  CountryName      countryName               select  int dr  id    FirstOrDefault

User · Answer

As per the title of the post I just needed to get all values from a specific column  Here is the code I used to achieve that        public static IEnumerable lt T gt  ColumnValues lt T gt  this DataColumn self                return self Table Select   Select dr   gt   T Convert ChangeType dr self   typeof T

User · Answer

Datatables have a  Select method  which returns a rows array according to the criteria you specify  Something like this   Dim oRows   As DataRow  oRows   dtCountries Select  CountryName       amp  userinput  amp        If oRows Count   0 Then      No rows found Else      At least one row found  Could be more than one End If   Of course  if userinput contains   character  it would raise an exception  like if you query the database   You should escape the   characters  I use a function to do that

User · Answer

foreach  DataRow row in Datatable Rows         if  row  CountryName   ToString      userInput                 return row  CountryID              While this may not compile directly you should get the idea  also I m sure it would be vastly superior to do the query through SQL as a huge datatable will take a long time to run through all the rows

User · Answer

I suggest such way based on extension methods   IEnumerable lt Int32 gt  countryIDs       dataTable      AsEnumerable        Where row   gt  row Field lt String gt   CountryName      countryName       Select row   gt  row Field lt Int32 gt   CountryID       System Data DataSetExtensions dll needs to be referenced

[c#] How to Get a Specific Column Value from a DataTable?

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