Can't iterate feature in while nested iteration

Question

I need to do some operation with every combinations of features in two FeatureClasses. The "for" iterating operator is very very slow-working, so I decided to try "while" operator and using FeatureCursor. So nested iteration I have like below:

 IFeatureCursor fcur1 = fc1.Search(null, false);
 IFeatureCursor fcur2 = fc2.Search(null, false);
 IFeature f1 = fcur1.NextFeature();
 IFeature f2 = fcur2.NextFeature();
 while (f1 != null)
 {
 //external cycle code
 MessageBox.Show("external cycle FID " + f1.Value[0].ToString());
 while (f2 != null)
 {
 //internal cycle code
 MessageBox.Show("internal cycle FID " + f1.Value[0].ToString());
 f2 = fcur2.NextFeature();
 }
 f1 = fcur1.NextFeature();
 }

For example, there are 3 features in each FeatureClass fc1 and fc2.

enter image description here

I use a MessageBoxes to show FID of feature f1 to understand what happens in external and internal iterations.

The expected order of MessageBoxes is:

external cycle FID 0
 internal cycle FID 0
 internal cycle FID 0
 internal cycle FID 0
external cycle FID 1
 internal cycle FID 1
 internal cycle FID 1
 internal cycle FID 1
external cycle FID 2
 internal cycle FID 2
 internal cycle FID 2
 internal cycle FID 2

But result of my code is:

external cycle FID 0
 internal cycle FID 0
 internal cycle FID 0
 internal cycle FID 0
external cycle FID 1
external cycle FID 2

So, external cycle operates with every feature f1, but internal cycle gets the first feature f1 only. Why another features f1 doesn't go to internal cycle?

• Barbarossa: You need to reset the fcur2 feature cursor for each fcur1 iteration
• Alex: How to reset the cursor? I can't see this method in fcur2 object
• Barbarossa: My mistake. I was thinking there was a reset method. Either way, you should reset the cursor by re-executing the query.

Answer 1

You need to reset the the feature cursor after going through each iteration. See my edits:

IFeatureCursor fcur1 = fc1.Search(null, false);
IFeatureCursor fcur2;
IFeature f1; 
IFeature f2;
 while ((f1 = fcur1.NextFeature()) != null)
 {
 //external cycle code
 MessageBox.Show("external cycle FID " + f1.Value[0].ToString());
 fcur2 = fc2.Search(null, false);
 while ((f2 = fcur2.NextFeature()) != null)
 {
 //internal cycle code
 MessageBox.Show("internal cycle FID " + f1.Value[0].ToString());
 }
 }

You may also want to release the second cursor after iterating through its features.

• Alex: It works!!! Barbarossa, many thanks! I didn't have a big hope that someone would introspect my long question