How do I loop through rows with a data reader in C

Question

I know I can use while dr Read         but that loops every field on my table  I want to retrieve all the values from the first row  and then second    and so on   Let s say I have a table like this   ID--------------Value1--------------Value2------------------Value3 1               hello               hello2                  hello3 2               hi1                  hi2                      hi3   first I want to get  hello  hello2 and hello3 and then go to the second row and get all the values   Is there a way to achieve this  I hope somebody understand what I mean   I am so sorry  this is solved now  I just wasn t coding right     And yeah the SqlDataReader Read   method does what it is supposed to do  again the mistake was mine

User · Answer

Suppose your DataTable has the following columns try this code   DataTable dt  new DataTable    txtTGrossWt Text   dt Compute  sum fldGrossWeight        ToString            0    dt Compute  sum fldGrossWeight        ToString    txtTOtherWt Text   dt Compute  sum fldOtherWeight        ToString            0    dt Compute  sum fldOtherWeight        ToString    txtTNetWt Text   dt Compute  sum fldNetWeight        ToString            0    dt Compute  sum fldNetWeight        ToString    txtFinalValue Text   dt Compute  sum fldValue        ToString            0    dt Compute  sum fldValue        ToString

User · Answer

int count   reader FieldCount  while reader Read          for int i   0   i  lt  count   i              Console WriteLine reader GetValue i              Note  if you have multiple grids  then   do       int count   reader FieldCount      while reader Read              for int i   0   i  lt  count   i                  Console WriteLine reader GetValue i                      while  reader NextResult

User · Answer

while  dr Read          for  int i   0  i  lt  dr FieldCount  i                  subjob Items Add dr i              to read rows in one colunmn

User · Answer

There is no way to get  the whole row  at once - you need to loop through the rows  and for each row  you need to read each column separately   using SqlDataReader rdr   cmd ExecuteReader          while  rdr Read                  string value1   rdr GetString 0           string value2   rdr GetString 1           string value3   rdr GetString 2             What you do with those strings that you read for each row is entirely up to you - you could store them into a class that you ve defined  or whatever

User · Answer

Actually the Read method iterating over records in a result set  In your case - over table rows  So you still can use it

User · Answer

That s the way the DataReader works  it s designed to read the database rows one at a time   while reader Read         var value1   reader GetValue 0      On first iteration will be hello   var value2   reader GetValue 1      On first iteration will be hello2   var value3   reader GetValue 2      On first iteration will be hello3

User · Answer

Or you can try to access the columns directly by name   while dr Read          string col1    string dr  Value1        string col2    string dr  Value2        string col3    string dr  Value3

User · Answer

How do I loop through rows with a data reader in C     IDataReader Read   advances the reader to the next row in the resultset   while reader Read            do whatever you d like to do for each row         So  for each iteration of your loop  you d do another loop  0 to reader FieldCount  and call reader GetValue i  for each field   The bigger question is what kind of structure do you want to use to hold that data

[c#] How do I loop through rows with a data reader in C#?

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