The C # API should look like AS3.0, see Flash AS3.0 implementation examples :

Here is the code for the ragdoll sample:
package TestBed{
import Box2D.Dynamics.*;
import Box2D.Collision.*;
import Box2D.Collision.Shapes.*;
import Box2D.Dynamics.Joints.*;
import Box2D.Dynamics.Contacts.*;
import Box2D.Common.*;
import Box2D.Common.Math.*;
public class TestRagdoll extends Test{
public function TestRagdoll(){
Main.m_aboutText.text = "Ragdolls";
var circ:b2CircleShape;
var box:b2PolygonShape;
var bd:b2BodyDef = new b2BodyDef();
var jd:b2RevoluteJointDef = new b2RevoluteJointDef();
var fixtureDef:b2FixtureDef = new b2FixtureDef();
for (var i:int = 0; i < 2; i++){
var startX:Number = 70 + Math.random() * 20 + 480 * i;
var startY:Number = 20 + Math.random() * 50;
bd.type = b2Body.b2_dynamicBody;
circ = new b2CircleShape( 12.5 / m_physScale );
fixtureDef.shape = circ;
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.3;
bd.position.Set(startX / m_physScale, startY / m_physScale);
var head:b2Body = m_world.CreateBody(bd);
head.CreateFixture(fixtureDef);
head.ApplyImpulse(new b2Vec2(Math.random() * 100 - 50, Math.random() * 100 - 50), head.GetWorldCenter());
box = new b2PolygonShape();
box.SetAsBox(15 / m_physScale, 10 / m_physScale);
fixtureDef.shape = box;
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.1;
bd.position.Set(startX / m_physScale, (startY + 28) / m_physScale);
var torso1:b2Body = m_world.CreateBody(bd);
torso1.CreateFixture(fixtureDef);
box = new b2PolygonShape();
box.SetAsBox(15 / m_physScale, 10 / m_physScale);
fixtureDef.shape = box;
bd.position.Set(startX / m_physScale, (startY + 43) / m_physScale);
var torso2:b2Body = m_world.CreateBody(bd);
torso2.CreateFixture(fixtureDef);
box.SetAsBox(15 / m_physScale, 10 / m_physScale);
fixtureDef.shape = box;
bd.position.Set(startX / m_physScale, (startY + 58) / m_physScale);
var torso3:b2Body = m_world.CreateBody(bd);
torso3.CreateFixture(fixtureDef);
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.1;
box = new b2PolygonShape();
box.SetAsBox(18 / m_physScale, 6.5 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX - 30) / m_physScale, (startY + 20) / m_physScale);
var upperArmL:b2Body = m_world.CreateBody(bd);
upperArmL.CreateFixture(fixtureDef);
box = new b2PolygonShape();
box.SetAsBox(18 / m_physScale, 6.5 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX + 30) / m_physScale, (startY + 20) / m_physScale);
var upperArmR:b2Body = m_world.CreateBody(bd);
upperArmR.CreateFixture(fixtureDef);
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.1;
box = new b2PolygonShape();
box.SetAsBox(17 / m_physScale, 6 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX - 57) / m_physScale, (startY + 20) / m_physScale);
var lowerArmL:b2Body = m_world.CreateBody(bd);
lowerArmL.CreateFixture(fixtureDef);
box = new b2PolygonShape();
box.SetAsBox(17 / m_physScale, 6 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX + 57) / m_physScale, (startY + 20) / m_physScale);
var lowerArmR:b2Body = m_world.CreateBody(bd);
lowerArmR.CreateFixture(fixtureDef);
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.1;
box = new b2PolygonShape();
box.SetAsBox(7.5 / m_physScale, 22 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX - 8) / m_physScale, (startY + 85) / m_physScale);
var upperLegL:b2Body = m_world.CreateBody(bd);
upperLegL.CreateFixture(fixtureDef);
box = new b2PolygonShape();
box.SetAsBox(7.5 / m_physScale, 22 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX + 8) / m_physScale, (startY + 85) / m_physScale);
var upperLegR:b2Body = m_world.CreateBody(bd);
upperLegR.CreateFixture(fixtureDef);
fixtureDef.density = 1.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.1;
box = new b2PolygonShape();
box.SetAsBox(6 / m_physScale, 20 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX - 8) / m_physScale, (startY + 120) / m_physScale);
var lowerLegL:b2Body = m_world.CreateBody(bd);
lowerLegL.CreateFixture(fixtureDef);
box = new b2PolygonShape();
box.SetAsBox(6 / m_physScale, 20 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((startX + 8) / m_physScale, (startY + 120) / m_physScale);
var lowerLegR:b2Body = m_world.CreateBody(bd);
lowerLegR.CreateFixture(fixtureDef);
jd.enableLimit = true;
jd.lowerAngle = -40 / (180/Math.PI);
jd.upperAngle = 40 / (180/Math.PI);
jd.Initialize(torso1, head, new b2Vec2(startX / m_physScale, (startY + 15) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -85 / (180/Math.PI);
jd.upperAngle = 130 / (180/Math.PI);
jd.Initialize(torso1, upperArmL, new b2Vec2((startX - 18) / m_physScale, (startY + 20) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -130 / (180/Math.PI);
jd.upperAngle = 85 / (180/Math.PI);
jd.Initialize(torso1, upperArmR, new b2Vec2((startX + 18) / m_physScale, (startY + 20) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -130 / (180/Math.PI);
jd.upperAngle = 10 / (180/Math.PI);
jd.Initialize(upperArmL, lowerArmL, new b2Vec2((startX - 45) / m_physScale, (startY + 20) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -10 / (180/Math.PI);
jd.upperAngle = 130 / (180/Math.PI);
jd.Initialize(upperArmR, lowerArmR, new b2Vec2((startX + 45) / m_physScale, (startY + 20) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -15 / (180/Math.PI);
jd.upperAngle = 15 / (180/Math.PI);
jd.Initialize(torso1, torso2, new b2Vec2(startX / m_physScale, (startY + 35) / m_physScale));
m_world.CreateJoint(jd);
jd.Initialize(torso2, torso3, new b2Vec2(startX / m_physScale, (startY + 50) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -25 / (180/Math.PI);
jd.upperAngle = 45 / (180/Math.PI);
jd.Initialize(torso3, upperLegL, new b2Vec2((startX - 8) / m_physScale, (startY + 72) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -45 / (180/Math.PI);
jd.upperAngle = 25 / (180/Math.PI);
jd.Initialize(torso3, upperLegR, new b2Vec2((startX + 8) / m_physScale, (startY + 72) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -25 / (180/Math.PI);
jd.upperAngle = 115 / (180/Math.PI);
jd.Initialize(upperLegL, lowerLegL, new b2Vec2((startX - 8) / m_physScale, (startY + 105) / m_physScale));
m_world.CreateJoint(jd);
jd.lowerAngle = -115 / (180/Math.PI);
jd.upperAngle = 25 / (180/Math.PI);
jd.Initialize(upperLegR, lowerLegR, new b2Vec2((startX + 8) / m_physScale, (startY + 105) / m_physScale));
m_world.CreateJoint(jd);
}
bd.type = b2Body.b2_staticBody;
fixtureDef.density = 0.0;
fixtureDef.friction = 0.4;
fixtureDef.restitution = 0.3;
for (var j:int = 1; j <= 10; j++) {
box = new b2PolygonShape();
box.SetAsBox((10*j) / m_physScale, 10 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((10*j) / m_physScale, (150 + 20*j) / m_physScale);
head = m_world.CreateBody(bd);
head.CreateFixture(fixtureDef);
}
for (var k:int = 1; k <= 10; k++){
box = new b2PolygonShape();
box.SetAsBox((10 * k) / m_physScale, 10 / m_physScale);
fixtureDef.shape = box;
bd.position.Set((640-10*k) / m_physScale, (150 + 20*k) / m_physScale);
head = m_world.CreateBody(bd);
head.CreateFixture(fixtureDef);
}
box = new b2PolygonShape();
box.SetAsBox(30 / m_physScale, 40 / m_physScale);
fixtureDef.shape = box;
bd.position.Set(320 / m_physScale, 320 / m_physScale);
head = m_world.CreateBody(bd);
head.CreateFixture(fixtureDef);
}
}
}