C# 在嵌套 Ifs 中处理 Else 条件

Question

I need to execute an else statement from a if , and another if inside it.

if (!BoxA_IsNull && !BoxB_IsNull && !BoxC_IsNull && !BoxD_IsNull) //Scenario 1
{
    if (BoxA == BoxB && BoxC == BoxD) //Scenario 2
    {
        //Do something
    }
}
else
{
    // Do something else if 
    // 1) Scenario 1 hits but not scenario 2
    // 2) Scenario 1 does not hit
}

May I know how can I go to else statement regardless if scenario 1 or scenario 2 hits?

Edit: Apologies on scenario confusion. Have edited as above in else statement

---

At the end I went with the following solution of

if ((!BoxA_IsNull && !BoxB_IsNull && !BoxC_IsNull && !BoxD_IsNull) && (BoxA == BoxB && BoxC == BoxD))
{
    //do something
}

Reason is because during if , it will hit 2nd comparison check if 1st null check fails. The purpose of my 1st null check is to prevent null exception during 2nd comparison check.

Answer 1

Store the conditions in boolean variables. Then you can reuse them.

bool nullCondition = !BoxA_IsNull && !BoxB_IsNull && !BoxC_IsNull && !BoxD_IsNull;
bool equalityCondition = BoxA == BoxB && BoxC == BoxD;

if (nullCondition && equalityCondition) 
{
  // Both conditions are true
}
else 
{
  // Any of equalitycondition or nullcondition is false
}

Answer 2

You could store the scenarios in two boolean variables, which makes the check more easily:

bool scenario1 = !BoxA_IsNull && !BoxB_IsNull && !BoxC_IsNull && !BoxD_IsNull;
bool scenario2 = BoxA == BoxB && BoxC == BoxD
if (scenario1)
{
    if (scenario2)
    {
        //do something
    }
}
if((scenario1 && !scenario2) || !scenario1)
{
    //do something else if either Scenario 1 or 2 hits.
}

Depending on what you are doing exactly, you could also give the variables more expressive names.

Answer 3

I'm not sure I'm understanding you question correctly; the logic you seem to want with your example is pretty simple:

if (!BoxA_IsNull && !BoxB_IsNull && !BoxC_IsNull && !BoxD_IsNull) 
{
    if (BoxA == BoxB && BoxC == BoxD)
    {
        //Scenario 1 & 2
    }
    else
    {
        //Scenario 1 hits but not scenario 2
    }
}
else
{
     //Scenario 1 does not hit
}