Experts,
I have a datatable with two columns:
1) One is Decimal
2) One is String
I write my filter query like:
var iFilterResult = from c in dataTable1.AsEnumerable()
where c.Field<string>("ACM_ACCOUNT_CODE").Contains(txtFindPrePaidExpenses.Text)
&& c.Field<string>("ACM_ACCOUNT_DESC").Contains(txtFindPrePaidExpenses.Text)
select new
{
ACM_ACCOUNT_CODE = c.Field<string>("ACM_ACCOUNT_CODE"),
ACM_ACCOUNT_DESC = c.Field<string>(" ACM_ACCOUNT_DESC")
};
gvSearchAccountGL.DataSource = iFilterResult;
gvSearchAccountGL.DataBind(); "
Here dataTable1 is Datatable Having Column
ACM_ACCOUNT_CODE of decimal type
ACM_ACCOUNT_DESC of string type.
use like Query for filter.
But it is not working
You're trying to use ACM_ACCOUNT_CODE as a string field - but you've said it's a decimal field.
It's not clear why you'd expect a decimal field to contain the same value as the description field. If you really want this, you could use:
c.Field<decimal>("ACM_ACCOUNT_CODE")
.ToString()
.Contains(txtFindPrePaidExpenses.Text)
... but I suspect you should rethink what the query is trying to do.
Related
I want to reformat the data without going back to the database and in a dynamic way
So that the user can specify what columns he wants to collect
how I can
Write an sql string and execute it like EXECUTE IMMEDIAT in Oracle
Inside C# Linq
want to do a lock like combining two or more fields (multiply - merge...)
ToTable
It only allows me to specify the names of existing fields
FillDataSorce(params P)
{
// p It is a variable containing the field to be queried
//Like
//field1 = d["field1"] ,
//field2 = d["field2"] ,
//field sum = d["field1"] +d["field2"]
BSo.DataSource = from d in dt.AsEnumerable()
select new
{
P.Select(p => p) //col3col2 = d["col1"] + d["col2"] Dynamic field example
};
}
I use System.Linq.Dynamic to query entities with dynamic 'where' expressions. I'm querying object that has property "newValue" of string type. Exemplary value would be : "{\"ProcessId\":764, \"ProcessLength\":1000}".
I can't use == because I want to find all hits where the property contains "ProcessId:764", regardless on the rest of the string. The thing is, that stored string contains escape sign "\" and double quotes and I can't figure out what it should like exactly..
dbContext.Processes.Where("#newValue.Contains(\"ProcessId\":764\")") brings error, however dbContext.Processes.Where("#newValue.Contains(\":764\")") works correctly. I guess it must be something with backslashes or double quotes in my query but can't figure it out on my own..
There are two things to note here:
If you know at compile time the column that should be queried (i.e., newValue), just use standard Linq: var list = items.Where(i => i.NewValue.Contains("904")).ToList().
If you do want to use dyanmic Linq, What you'd usually want is to apply Where on some column, e.g. Where("SomeColumn.Contains("something")"), or Where("SomeColumn.Contains(#0)", new string[] {"something"}).
So, in your case, this should work: items.Where("newValue.Contains(\"904\")").
Doing Where("#newValue.Contains("something")") doesn't really make sense, since #newValue would be parsed as a string literal. See also this comment on a similiar question.
Here' a quick example:
public static void Main(string[] args)
{
var items = new []
{
new { Id = "1", Title = "ProcessId: 123"},
new { Id = "4", Title = "ProcessId: 456"},
new { Id = "7", Title = "ProcessId: 789"},
}.ToList();
// returns null, because the string "Title" doesn't contain the string "7"
var res1 = items.Where("#0.Contains(\"7\")", new string[] {"Title"}).FirstOrDefault();
// works - returns the 3rd element of the array
var res2a = items.Where("Title.Contains(#0)", new string[] {"ProcessId: 789"}).FirstOrDefault();
var res2b = items.Where("Title.Contains(\"ProcessId: 789\")").FirstOrDefault();
}
#HeyJude Thanks for the effort, but I still can't get it to work. It has somehow gone wronger and now I can't even fetch correct rows giving only ProcessId number..
Let me give you more detailed description of my setup. In the database there's a table with column "NewValue", I use this column to store json string of current (for the time of creating row in the table) representation of some object e.g. object Process. So the column stores for example string of {"ProcessId":904,"ProcessLength":1000}. To fetch this data from db I create collection of table's records: var items = (from l in db.JDE_Logs
join u in db.JDE_Users on l.UserId equals u.UserId
join t in db.JDE_Tenants on l.TenantId equals t.TenantId
where l.TenantId == tenants.FirstOrDefault().TenantId && l.Timestamp >= dFrom && l.Timestamp <= dTo
orderby l.Timestamp descending
select new //ExtLog
{
LogId = l.LogId,
TimeStamp = l.Timestamp,
TenantId = t.TenantId,
TenantName = t.TenantName,
UserId = l.UserId,
UserName = u.Name + " " + u.Surname,
Description = l.Description,
OldValue = l.OldValue,
NewValue = l.NewValue
});. Then I query it to find matching rows for given ProcessId number e.g. query = "#NewValue.Contains(\"904,)\")";
items = items.Where(query);
This should fetch back all records where NewValue column contains the query string, but this doesn't work. It compiles and 'works' but no data are fetched or fetched are only those records where 904 appears later in the string. Sounds stupid but this is what it is.
What should the query string look like to fetch all records containing "ProcessId":904?
Importing a spreadsheet I have filled a DataTable object with that data and returns expected results.
Attempting to put this into a format I can easily query to search for problem records I have done the following
public void Something(DataTable dt)
{
var data = from row in dt.AsEnumerable()
select row["Order"].ToString();
}
Works as expected giving me a list of orders. However I cannot add other fields to this EnumerableRowCollection. Attempting to add other fields as follows gives me an error
public void Something(DataTable dt)
{
// row["Version"] throws an error on me
var data = from row in dt.AsEnumerable()
select row["Order"].ToString(), row["Version"].ToString();
}
Error: "A local variable named 'row' cannot be declared in this scope because it would give a different meaning to 'row' which is already used in a 'child' scope to donate something else"
I'm thinking I need to alias the column name but I'm having no luck. What am I missing here?
It sounds like you're writing a bad select statement. Try the following:
public void Something(DataTable dt)
{
var data = from row in dt.AsEnumerable()
select new {
Order = row["Order"].ToString(),
Something = row["Something"].ToString(),
Customer = row["Customer"].ToString(),
Address = row["Address"].ToString()
};
}
That will create a new collection of Anonymously Typed objects that you can iterate over and use as needed. Keep in mind, though, that you want be able to return data from the function. If you need that functionality, you need to create a concrete type to use (in place of anonymous types).
I think you should use select new like this query for example:
var q = from o in db.Orders
where o.Products.ProductName.StartsWith("Asset") &&
o.PaymentApproved == true
select new { name = o.Contacts.FirstName + " " +
o.Contacts.LastName,
product = o.Products.ProductName,
version = o.Products.Version +
(o.Products.SubVersion * 0.1)
};
You probably want the following.
var data = from row
in dt.AsEnumerable()
select new { Order = row["Order"].ToString(), Version = row["Version"].ToString() };
I have a collection of string names, few names starts with X100,x200,x121 which has numeric values.
I'm using LinQ to loop thro and also using a where clause to filter those names that has integer values like x"100." Which is the best way to do accompolish this?.
is it possible to use Func or Action on the items for checking each string variable.My
where clause in expression looks something like this
var columns = from c in factory.GetColumnNames("eventNames")
where c.Substring(1) // I dont know what to do next
select c;
.if the next string is "c.substring(1)" integer obviously the names are wrong.So is there any best way to do this check and return a string collection
To find all strings that contain an integer, you could use
var columns = from c in factory.GetColumnNames("eventNames")
where Regex.IsMatch(c, #"\d+")
select c;
Try this to select all the rows that are like "x100" etc.
int tmp;
var columns = from c in factory.GetColumnNames("eventNames")
where int.TryParse(c.Substring(1), out tmp)
select c;
Try this to select all rows, converting "x100" to "100" and leaving the rest as is.
int tmp;
var columns = from c in factory.GetColumnNames("eventNames")
select (int.TryParse(c.Substring(1), out tmp) ? tmp.ToString() : c);
If neither of these are what you want please clarify.
Try something like:
var columns = from c in factory.GetColumnNames("eventNames")
where CharactersAfterFirstAreInteger(c)
select c;
private bool CharactersAfterFirstAreInteger(string stringToCheck)
{
var subString = stringToCheck.SubString(1);
int result = 0;
return int.TryParse(subString, out result);
}
This gives you the flexibility to alter the signature of CharactersAfterFirstAreInteger, if you needed to, so you could perform additional checks, for example, so that only values where the numeric part were greater than 200 were returned..
I am trying to boild my treeview at runtime from a DataTable that is returned from a LINQ query. The Fields returned are:
NAME = CaseNoteID | ContactDate | ParentNote
TYPE = Guid | DateTime | Guid
The ParentNote field matches a entry in the CaseNoteID column. The Select(filter) is giving me a runtime error of Cannot find column [ea8428e4]. That alphanumeric is the first section of one of the Guids. When I step thru my code filter = "ParentNote=ea8428e4-1274-42e8-a31c-f57dc2f189a4"
What am I missing?
var tmpCNoteID = dr["CaseNoteID"].ToString();
var filter = "ParentNote="+tmpCNoteID;
DataRow[] childRows = cNoteDT.Select(filter);
Try enclosing the GUID with single quotes:
var filter = "ParentNote='"+tmpCNoteID+"'";
I know this is an old thread, but I wanted to add an addendum to it. When using the IN operator with a Guid (ex: ParentNote IN ( , , etc. ) ) then single quotes are no longer accepted. In that case, the CONVERT method (suggested by granadaCoder) is necessary. (Single quotes raise an exception about comparing a Guid to a string with the '=' operator... which we actually aren't using.)
Details: I inherited some legacy code that built a large filter string in the format: MyColumn = '11111111-2222-3333-4444-555555555555' OR MyColumn = '11111111-2222-3333-4444-555555555555' ....
When the number of guids (and, therefore the number of OR clauses) got to be too large, this caused a stack overflow exception. By replacing the numerous OR clauses with an IN clause, I was able to set the filter without an exception. But using an IN clause means having to use the CONVERT approach.
this should work :
var tmpCNoteID = dr["CaseNoteID"].ToString();
var filter = "ParentNote=\""+tmpCNoteID+"\"";
DataRow[] childRows = cNoteDT.Select(filter);
Here is one method I use:
MyStrongDataSet ds = new MyStrongDataSet();
Guid myUuid = new Guid("11111111-2222-3333-4444-555555555555");
System.Data.DataRow[] rows = ds.MyStrongTable.Select("MyGuidProperty = (CONVERT('" + myUuid.ToString("N") + "', 'System.Guid'))");
//Fish out a single row if need be and cast to a strong row
if (null != rows)
{
if (rows.Length > 0)
{
MyStrongDataSet.MyStrongTableRow returnRow = rows[0] as MyStrongDataSet.MyStrongTableRow;
return returnRow;
}
}
return null;
Here is a slight variation:
string filterSql = "MyGuidProperty ='{0}'";
filterSql = string.Format(filterSql, Guid.NewGuid().ToString("D"));