How to set conditional breakpoints in Visual Studio?

Is there an easy way to set conditional breakpoints in Visual Studio?

If I want to hit a breakpoint only when the value of a variable becomes something, how can I do it?

Answers


Set a breakpoint as usual. Right click it. Click Condition.


When you are using Express edition you can try this:

#if DEBUG
    if( fooVariable == true )
        System.Diagnostics.Debugger.Break();
#endif

if statement makes sure that in release build breakepoint will not be present.


Visual Studio provides lots of options for conditional breakpoints:

To set any of these you

  1. Set a break point
  2. Right Click over the break point, and in the popup menu you select an option that suites you.

These options are as follows:

  • You can set a condition, based off of a code expression that you supply (select Condition from the popup menu). For instance you can specify that foo == 8 or some other expression.
  • You can make breakpoints trigger after they have been hit a certain number of times. (select Hit Count from the popup menu). This is a fun option to play with as you actually aren't limited to breaking on a certain hit count, but you have options for a few other scenario's as well. I'll leave it to you to explore the possibilities.
  • You can Set filters on the Process ID, thread ID, and machine name (select Filter from the popup menu)

Just another way of doing it, (or if you are using express) add the condition in code:

if(yourCondition)
{
    System.Diagnostics.Debugger.Break();
}

  1. Set breakpoint on the line
  2. Right clik on RED ball
  3. Chose conditioal breakpoint
  4. Setup condition

Writing the actual condition can be the tricky part, so I tend to

  1. Set a regular breakpoint
  2. Run the code until the breakpoint is hit for the first time
  3. Use the Immediate Window (Debug > Windows > Immediate) to test your expression.
  4. Right-click the breakpoint, click Condition and paste in your expression.

Advantages of using the Immediate window

  • It has intellisense
  • You can be sure that the variables in the expression are in scope when the expression is evaluated
  • You can be sure your expression returns true or false

This example breaks when the code is referring to a table with name "Setting"

table.GetTableName().Contains("Setting")

  1. Set a breakpoint as usual.
  2. Right-click on the breakpoint marker
  3. Click "Condition..."
  4. Write a condition, you may use variable names
  5. Select either "Is True" or "Has Changed"

Create a breakpoint as you normally would, right click the red dot and select "condition".


  1. Set a breakpoint as usual
  2. Right click on the breakpoint and select Condition
  3. You'll see a dialog that says "Breakpoint Condition"
  4. Put a condition in the field e.g. "i==5"

The breakpoint will only get hit when i is 5.


On Visual Studio 6.0

Alt+F9!!!


Set the breakpoint as you do normally, right click the break point and select condion option and sets your condition.


Create a conditional function breakpoint

1)In the Breakpoints window, click New to create a new breakpoint.

2) On the Function tab, type Reverse for Function. Type 1 for Line, type 1 for Character, and then set Language to Basic.

3) Click Condition and make sure that the Condition check box is selected. Type instr.length > 0 for Condition, make sure that the is true option is selected, and then click OK.

4) In the New Breakpoint dialog box, click OK.

5)On the Debug menu, click Start.


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