logo
small logo
  • Products
  • Buy
  • Support
  • About
  • Customer panel Support
    • en
    • de
    • JP
    • ZH
  • Home
  • /
  • Articles
  • /
  • Event Report.Custom Calc - pre-processing of the input data
  • How to use WebReport with ASP .NET Web Core application

    January 17, 2018

    Recently FastReport introduced a new library under the .NET - FastReport Core platform. This is

    read more
  • Want to generate tables for a user - Excel or OpenOffice Calc?

    October 8, 2020

    Tables. For centuries, they have been used to present similar data for record-keeping, counting amounts,

    read more
  • How to make report inheritance in FastReport.NET

    January 29, 2021

    When you are tasked with creating a large number of reports within one corporate style,

    read more
  • How to protect your PDF?

    November 30, 2020

    On the Data protection day, we decided to prepare an article about the PDF documents

    read more
  • How to programmatically set the default email client settings for sending emails from FastReport.NET

    February 12, 2021

    Like many other report generators, FastReport .NET allows you to send a report via email

    read more

Event Report.Custom Calc - pre-processing of the input data

August 13, 2017

New CustomCalc event for the Report object is called when evaluating an expression in an object or when you receive data back from the data source. So we can use this event to intercept the data and spoofing. When this can be useful? For example, when you need to filter the values in the incoming data or to replace any row.

Let's look at an example. Сreate a simple WindowsForms application. Add the data source to the project, and the DataSet component. Also, place the component Report on the form.

In the drop-down menu of the Report component, select the item “Select Data Source”:

 

And choose our data source.

Now, select the item “Design Report” from the same menu. To demonstrate, I added a couple of fields from the Employee table:

 

For interest's see how the report looks now:

 

Save the report and close the Report Designer. Add a button to the form. And click event for it:

1
2
3
4
5
6
7
8
9
10
11
private void Run_Click(object sender, EventArgs e)
 
 {
 
 report1.Load("D://Reports//Simple.frx");
 
 report1.Prepare();
 
 report1.ShowPrepared();
 
 }

 Here, everything is banal. I have uploaded created earlier report. Then prepared it and showed.

And now, add the event CustomCalc for the report1 object:

 

1
2
3
4
5
6
7
8
9
10
11
12
13
 private void report1_CustomCalc(object sender, FastReport.CustomCalcEventArgs e)
 
 {
 
 if (e.CalculatedObject.Equals("Roberto") )
 
 {
 
 e.CalculatedObject = "Test Name";
 
 }
 
 }

 Here we intercept the needed data and replaces them. All data passes through CalculatedObject object during construction of the report. We catch the needed information "Roberto". And replace them.

You can replace the entire data field. In this case, the condition would look like this:

1
if (e.Expression.IndexOf("employee.FirstName") != -1)

 We wrote the code for the data substitution directly in the event handler CustomCalc. You can also assign the event handler directly in the code, for example in MVC application. With a convenient location in the application code we write:

1
report1.CustomCalc += FReport_CustomCalc;

  And the event handler:

1
2
3
4
5
6
7
8
9
10
11
12
13
private void FReport_CustomCalc(object sender, CustomCalcEventArgs e)
 
 {
 
 if (e.Expression.IndexOf("Employees.FirstName") != -1)
 
 { 
 
 e.CalculatedObject = "Test Name";
 
 }
 
 }

 Run the application. Click the button and see our report:

 

Let's compare this screenshot with one that was made earlier. As you can see, the first entry and the name of the employee Roberto put in a condition and has been replaced by Test Name.

Thus, we have a way to replace some of the data in the report. It probably will be used at sophisticated users of FastReport.

about product buy
avatar
Dmitriy Fedyashov
Technical Writer
Fast Reports Team: Dmitriy Fedyashov - Technical Writer at Fast Reports
.NET FastReport

Add comment
logo
  • 800-985-8986 (English, US)
  • +4930568373928 (German)
  • +55 19 98147-8148 (Portuguese)
  • info@fast-report.com
  • 901 N Pitt Str #325 Alexandria VA 22314
  • Buy
  • Download
  • Documentation
  • Testimonials
  • How to uninstall
  • FAQ
  • Tutorial Video
  • Forum
  • Support SLA
  • Articles
  • Our News
  • Press about us
  • Resellers
  • Extended licensing
  • Contact us

© 1998-2023 by Fast Reports Inc.

  • Privacy Policy

Trustpilot